diff --git a/include/asterisk/adsi.h b/include/asterisk/adsi.h
index c4ffedda16..31db2acb95 100644
--- a/include/asterisk/adsi.h
+++ b/include/asterisk/adsi.h
@@ -24,7 +24,6 @@
 #define _ASTERISK_ADSI_H
 
 #include "asterisk/callerid.h"
-#include "asterisk/optional_api.h"
 
 /*! \name ADSI parameters */
 /*@{ */
@@ -121,11 +120,13 @@
 #define ADSI_DIR_FROM_LEFT (0)
 #define ADSI_DIR_FROM_RIGHT (1)
 
+#define AST_ADSI_VERSION 1
+
 /*@} */
 
-AST_OPTIONAL_API(int, ast_adsi_begin_download, (struct ast_channel *chan, char *service, unsigned char *fdn, unsigned char *sec, int version), { return 0; });
+int ast_adsi_begin_download(struct ast_channel *chan, char *service, unsigned char *fdn, unsigned char *sec, int version);
 
-AST_OPTIONAL_API(int, ast_adsi_end_download, (struct ast_channel *chan), { return 0; });
+int ast_adsi_end_download(struct ast_channel *chan);
 
 /*! Restore ADSI initialization (for applications that play with ADSI
  *   and want to restore it to normal.  If you touch "INFO" then you
@@ -135,7 +136,7 @@ AST_OPTIONAL_API(int, ast_adsi_end_download, (struct ast_channel *chan), { retur
  * \retval 0 on success (or adsi unavailable)
  * \retval -1 on hangup
  */
-AST_OPTIONAL_API(int, ast_adsi_channel_restore, (struct ast_channel *chan), { return 0; });
+int ast_adsi_channel_restore(struct ast_channel *chan);
 
 /*!
  * \brief Display some stuff on the screen
@@ -147,7 +148,7 @@ AST_OPTIONAL_API(int, ast_adsi_channel_restore, (struct ast_channel *chan), { re
  * \retval 0 on success (or adsi unavailable)
  * \retval -1 on hangup
  */
-AST_OPTIONAL_API(int, ast_adsi_print, (struct ast_channel *chan, char **lines, int *align, int voice), { return 0; });
+int ast_adsi_print(struct ast_channel *chan, char **lines, int *align, int voice);
 
 /*!
  * \brief Check if scripts for a given app are already loaded.
@@ -161,16 +162,16 @@ AST_OPTIONAL_API(int, ast_adsi_print, (struct ast_channel *chan, char **lines, i
  * \retval -1 on hangup
  * \retval 1 if script already loaded.
  */
-AST_OPTIONAL_API(int, ast_adsi_load_session, (struct ast_channel *chan, unsigned char *app, int ver, int data), { return 0; });
-AST_OPTIONAL_API(int, ast_adsi_unload_session, (struct ast_channel *chan), { return 0; });
+int ast_adsi_load_session(struct ast_channel *chan, unsigned char *app, int ver, int data);
+int ast_adsi_unload_session(struct ast_channel *chan);
 
 /* ADSI Layer 2 transmission functions */
-AST_OPTIONAL_API(int, ast_adsi_transmit_message, (struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype), { return 0; });
-AST_OPTIONAL_API(int, ast_adsi_transmit_message_full, (struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype, int dowait), { return 0; });
+int ast_adsi_transmit_message(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype);
+int ast_adsi_transmit_message_full(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype, int dowait);
 /*! Read some encoded DTMF data.
  * Returns number of bytes received
  */
-AST_OPTIONAL_API(int, ast_adsi_read_encoded_dtmf, (struct ast_channel *chan, unsigned char *buf, int maxlen), { return 0; });
+int ast_adsi_read_encoded_dtmf(struct ast_channel *chan, unsigned char *buf, int maxlen);
 
 /* ADSI Layer 3 creation functions */
 
@@ -184,22 +185,22 @@ AST_OPTIONAL_API(int, ast_adsi_read_encoded_dtmf, (struct ast_channel *chan, uns
  * \retval -1 on error.
  */
 
-AST_OPTIONAL_API(int, ast_adsi_connect_session, (unsigned char *buf, unsigned char *fdn, int ver), { return 0; });
+int ast_adsi_connect_session(unsigned char *buf, unsigned char *fdn, int ver);
 
 /*! Build Query CPE ID of equipment.
  *  Returns number of bytes added to message
  */
-AST_OPTIONAL_API(int, ast_adsi_query_cpeid, (unsigned char *buf), { return 0; });
-AST_OPTIONAL_API(int, ast_adsi_query_cpeinfo, (unsigned char *buf), { return 0; });
+int ast_adsi_query_cpeid(unsigned char *buf);
+int ast_adsi_query_cpeinfo(unsigned char *buf);
 
 /*! Get CPE ID from an attached ADSI compatible CPE.
  * Returns 1 on success, storing 4 bytes of CPE ID at buf
  * or -1 on hangup, or 0 if there was no hangup but it failed to find the
  * device ID.  Returns to voice mode if "voice" is non-zero.
  */
-AST_OPTIONAL_API(int, ast_adsi_get_cpeid, (struct ast_channel *chan, unsigned char *cpeid, int voice), { return 0; });
+int ast_adsi_get_cpeid(struct ast_channel *chan, unsigned char *cpeid, int voice);
 
-AST_OPTIONAL_API(int, ast_adsi_get_cpeinfo, (struct ast_channel *chan, int *width, int *height, int *buttons, int voice), { return 0; });
+int ast_adsi_get_cpeinfo(struct ast_channel *chan, int *width, int *height, int *buttons, int voice);
 
 /*!
  * \brief Begin an ADSI script download
@@ -213,7 +214,7 @@ AST_OPTIONAL_API(int, ast_adsi_get_cpeinfo, (struct ast_channel *chan, int *widt
  * \retval -1 on error.
  */
 
-AST_OPTIONAL_API(int, ast_adsi_download_connect, (unsigned char *buf, char *service, unsigned char *fdn, unsigned char *sec, int ver), { return 0; });
+int ast_adsi_download_connect(unsigned char *buf, char *service, unsigned char *fdn, unsigned char *sec, int ver);
 
 /*!
  * \brief Disconnects a running session.
@@ -222,7 +223,7 @@ AST_OPTIONAL_API(int, ast_adsi_download_connect, (unsigned char *buf, char *serv
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_disconnect_session, (unsigned char *buf), { return 0; });
+int ast_adsi_disconnect_session(unsigned char *buf);
 
 /*!
  * \brief Disconnects (and hopefully saves) a downloaded script
@@ -231,7 +232,7 @@ AST_OPTIONAL_API(int, ast_adsi_disconnect_session, (unsigned char *buf), { retur
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_download_disconnect, (unsigned char *buf), { return 0; });
+int ast_adsi_download_disconnect(unsigned char *buf);
 
 /*!
  * \brief Puts CPE in data mode.
@@ -240,9 +241,9 @@ AST_OPTIONAL_API(int, ast_adsi_download_disconnect, (unsigned char *buf), { retu
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_data_mode, (unsigned char *buf), { return 0; });
-AST_OPTIONAL_API(int, ast_adsi_clear_soft_keys, (unsigned char *buf), { return 0; });
-AST_OPTIONAL_API(int, ast_adsi_clear_screen, (unsigned char *buf), { return 0; });
+int ast_adsi_data_mode(unsigned char *buf);
+int ast_adsi_clear_soft_keys(unsigned char *buf);
+int ast_adsi_clear_screen(unsigned char *buf);
 
 /*!
  * \brief Puts CPE in voice mode.
@@ -252,13 +253,13 @@ AST_OPTIONAL_API(int, ast_adsi_clear_screen, (unsigned char *buf), { return 0; }
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_voice_mode, (unsigned char *buf, int when), { return 0; });
+int ast_adsi_voice_mode(unsigned char *buf, int when);
 
 /*!
  * \brief Returns non-zero if Channel does or might support ADSI
  * \param chan Channel to check
  */
-AST_OPTIONAL_API(int, ast_adsi_available, (struct ast_channel *chan), { return 0; });
+int ast_adsi_available(struct ast_channel *chan);
 
 /*!
  * \brief Loads a line of info into the display.
@@ -274,7 +275,7 @@ AST_OPTIONAL_API(int, ast_adsi_available, (struct ast_channel *chan), { return 0
  * \retval -1 on error.
  */
 
-AST_OPTIONAL_API(int, ast_adsi_display, (unsigned char *buf, int page, int line, int just, int wrap, char *col1, char *col2), { return 0; });
+int ast_adsi_display(unsigned char *buf, int page, int line, int just, int wrap, char *col1, char *col2);
 
 /*!
  * \brief Sets the current line and page.
@@ -286,7 +287,7 @@ AST_OPTIONAL_API(int, ast_adsi_display, (unsigned char *buf, int page, int line,
  * \retval -1 on error.
  */
 
-AST_OPTIONAL_API(int, ast_adsi_set_line, (unsigned char *buf, int page, int line), { return 0; });
+int ast_adsi_set_line(unsigned char *buf, int page, int line);
 
 /*!
  * \brief Creates "load soft key" parameters
@@ -300,7 +301,7 @@ AST_OPTIONAL_API(int, ast_adsi_set_line, (unsigned char *buf, int page, int line
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_load_soft_key, (unsigned char *buf, int key, const char *llabel, const char *slabel, char *ret, int data), { return 0; });
+int ast_adsi_load_soft_key(unsigned char *buf, int key, const char *llabel, const char *slabel, char *ret, int data);
 
 /*!
  * \brief Set which soft keys should be displayed
@@ -311,7 +312,7 @@ AST_OPTIONAL_API(int, ast_adsi_load_soft_key, (unsigned char *buf, int key, cons
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_set_keys, (unsigned char *buf, unsigned char *keys), { return 0; });
+int ast_adsi_set_keys(unsigned char *buf, unsigned char *keys);
 
 /*!
  * \brief Set input information
@@ -325,7 +326,7 @@ AST_OPTIONAL_API(int, ast_adsi_set_keys, (unsigned char *buf, unsigned char *key
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_input_control, (unsigned char *buf, int page, int line, int display, int format, int just), { return 0; });
+int ast_adsi_input_control(unsigned char *buf, int page, int line, int display, int format, int just);
 
 /*!
  * \brief Set input format
@@ -339,7 +340,41 @@ AST_OPTIONAL_API(int, ast_adsi_input_control, (unsigned char *buf, int page, int
  * \retval number of bytes added to buffer
  * \retval -1 on error.
  */
-AST_OPTIONAL_API(int, ast_adsi_input_format, (unsigned char *buf, int num, int dir, int wrap, char *format1, char *format2), { return 0; });
+int ast_adsi_input_format(unsigned char *buf, int num, int dir, int wrap, char *format1, char *format2);
+
+struct adsi_funcs {
+	unsigned int version;
+	int (*begin_download)(struct ast_channel *chan, char *service, unsigned char *fdn, unsigned char *sec, int version);
+	int (*end_download)(struct ast_channel *chan);
+	int (*channel_restore) (struct ast_channel *chan);
+	int (*print) (struct ast_channel *chan, char **lines, int *align, int voice);
+	int (*load_session) (struct ast_channel *chan, unsigned char *app, int ver, int data);
+	int (*unload_session) (struct ast_channel *chan);
+	int (*transmit_message) (struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype);
+	int (*transmit_message_full) (struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype, int dowait);
+	int (*read_encoded_dtmf) (struct ast_channel *chan, unsigned char *buf, int maxlen);
+	int (*connect_session) (unsigned char *buf, unsigned char *fdn, int ver);
+	int (*query_cpeid) (unsigned char *buf);
+	int (*query_cpeinfo) (unsigned char *buf);
+	int (*get_cpeid) (struct ast_channel *chan, unsigned char *cpeid, int voice);
+	int (*get_cpeinfo) (struct ast_channel *chan, int *width, int *height, int *buttons, int voice);
+	int (*download_connect) (unsigned char *buf, char *service, unsigned char *fdn, unsigned char *sec, int ver);
+	int (*disconnect_session) (unsigned char *buf);
+	int (*download_disconnect) (unsigned char *buf);
+	int (*data_mode) (unsigned char *buf);
+	int (*clear_soft_keys) (unsigned char *buf);
+	int (*clear_screen) (unsigned char *buf);
+	int (*voice_mode) (unsigned char *buf, int when);
+	int (*available) (struct ast_channel *chan);
+	int (*display) (unsigned char *buf, int page, int line, int just, int wrap, char *col1, char *col2);
+	int (*set_line) (unsigned char *buf, int page, int line);
+	int (*load_soft_key) (unsigned char *buf, int key, const char *llabel, const char *slabel, char *ret, int data);
+	int (*set_keys) (unsigned char *buf, unsigned char *keys);
+	int (*input_control) (unsigned char *buf, int page, int line, int display, int format, int just);
+	int (*input_format) (unsigned char *buf, int num, int dir, int wrap, char *format1, char *format2);
+};
+
+void ast_adsi_install_funcs(const struct adsi_funcs *funcs);
 
 #endif /* _ASTERISK_ADSI_H */
 
diff --git a/main/Makefile b/main/Makefile
index 728b80591a..e29e88fbde 100644
--- a/main/Makefile
+++ b/main/Makefile
@@ -26,9 +26,6 @@ OBJS=$(filter-out $(OBJSFILTER),$(SRC:.c=.o))
 # otherwise modules will not have them available if none of the static
 # objects use it.
 OBJS+=stdtime/localtime.o
-ifneq ($(firstword $(subst :, ,$(WEAKREF))),1)
-OBJS+=../res/res_adsi.o
-endif
 
 AST_LIBS += $(OPENSSL_LIB)
 AST_LIBS += $(BKTR_LIB)
diff --git a/main/adsi.c b/main/adsi.c
new file mode 100644
index 0000000000..870b132913
--- /dev/null
+++ b/main/adsi.c
@@ -0,0 +1,351 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2012, Digium, Inc.
+ *
+ * Mark Michelson <mmichelson@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ * \brief ADSI Support (built upon Caller*ID)
+ */
+
+#include "asterisk.h"
+
+#include "asterisk/adsi.h"
+#include "asterisk/lock.h"
+
+static const struct adsi_funcs *installed_funcs;
+static const int current_adsi_version = AST_ADSI_VERSION;
+AST_RWLOCK_DEFINE_STATIC(func_lock);
+
+int ast_adsi_begin_download(struct ast_channel *chan, char *service, unsigned char *fdn, unsigned char *sec, int version)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->begin_download) {
+		res = installed_funcs->begin_download(chan, service, fdn, sec, version);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_end_download(struct ast_channel *chan)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->end_download) {
+		res = installed_funcs->end_download(chan);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_channel_restore(struct ast_channel *chan)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->channel_restore) {
+		res = installed_funcs->channel_restore(chan);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_print(struct ast_channel *chan, char **lines, int *align, int voice)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->print) {
+		res = installed_funcs->print(chan, lines, align, voice);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_load_session(struct ast_channel *chan, unsigned char *app, int ver, int data)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->load_session) {
+		res = installed_funcs->load_session(chan, app, ver, data);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_unload_session(struct ast_channel *chan)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->unload_session) {
+		res = installed_funcs->unload_session(chan);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_transmit_message(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->transmit_message) {
+		res = installed_funcs->transmit_message(chan, msg, msglen, msgtype);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_transmit_message_full(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype, int dowait)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->transmit_message_full) {
+		res = installed_funcs->transmit_message_full(chan, msg, msglen, msgtype, dowait);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_read_encoded_dtmf(struct ast_channel *chan, unsigned char *buf, int maxlen)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->read_encoded_dtmf) {
+		res = installed_funcs->read_encoded_dtmf(chan, buf, maxlen);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_connect_session(unsigned char *buf, unsigned char *fdn, int ver)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->connect_session) {
+		res = installed_funcs->connect_session(buf, fdn, ver);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_query_cpeid(unsigned char *buf)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->query_cpeid) {
+		res = installed_funcs->query_cpeid(buf);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_query_cpeinfo(unsigned char *buf)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->query_cpeinfo) {
+		res = installed_funcs->query_cpeinfo(buf);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_get_cpeid(struct ast_channel *chan, unsigned char *cpeid, int voice)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->get_cpeid) {
+		res = installed_funcs->get_cpeid(chan, cpeid, voice);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_get_cpeinfo(struct ast_channel *chan, int *width, int *height, int *buttons, int voice)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->get_cpeinfo) {
+		res = installed_funcs->get_cpeinfo(chan, width, height, buttons, voice);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_download_connect(unsigned char *buf, char *service, unsigned char *fdn, unsigned char *sec, int ver)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->download_connect) {
+		res = installed_funcs->download_connect(buf, service, fdn, sec, ver);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_disconnect_session(unsigned char *buf)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->disconnect_session) {
+		res = installed_funcs->disconnect_session(buf);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_download_disconnect(unsigned char *buf)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->download_disconnect) {
+		res = installed_funcs->download_disconnect(buf);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_data_mode(unsigned char *buf)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->data_mode) {
+		res = installed_funcs->data_mode(buf);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_clear_soft_keys(unsigned char *buf)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->clear_soft_keys) {
+		res = installed_funcs->clear_soft_keys(buf);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_clear_screen(unsigned char *buf)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->clear_screen) {
+		res = installed_funcs->clear_screen(buf);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_voice_mode(unsigned char *buf, int when)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->voice_mode) {
+		res = installed_funcs->voice_mode(buf, when);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_available(struct ast_channel *chan)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->available) {
+		res = installed_funcs->available(chan);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_display(unsigned char *buf, int page, int line, int just, int wrap, char *col1, char *col2)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->display) {
+		res = installed_funcs->display(buf, page, line, just, wrap, col1, col2);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_set_line(unsigned char *buf, int page, int line)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->set_line) {
+		res = installed_funcs->set_line(buf, page, line);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_load_soft_key(unsigned char *buf, int key, const char *llabel, const char *slabel, char *ret, int data)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->load_soft_key) {
+		res = installed_funcs->load_soft_key(buf, key, llabel, slabel, ret, data);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_set_keys(unsigned char *buf, unsigned char *keys)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->set_keys) {
+		res = installed_funcs->set_keys(buf, keys);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_input_control(unsigned char *buf, int page, int line, int display, int format, int just)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->input_control) {
+		res = installed_funcs->input_control(buf, page, line, display, format, just);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+int ast_adsi_input_format(unsigned char *buf, int num, int dir, int wrap, char *format1, char *format2)
+{
+	int res = 0;
+	ast_rwlock_rdlock(&func_lock);
+	if (installed_funcs && installed_funcs->input_format) {
+		res = installed_funcs->input_format(buf, num, dir, wrap, format1, format2);
+	}
+	ast_rwlock_unlock(&func_lock);
+	return res;
+}
+
+void ast_adsi_install_funcs(const struct adsi_funcs *funcs)
+{
+	if (funcs->version < current_adsi_version) {
+		ast_log(LOG_WARNING, "Cannot install ADSI function pointers due to version mismatch."
+				"Ours: %u, Theirs: %u\n", current_adsi_version, funcs->version);
+		return;
+	}
+
+	ast_rwlock_wrlock(&func_lock);
+	installed_funcs = funcs;
+	ast_rwlock_unlock(&func_lock);
+}
diff --git a/res/res_adsi.c b/res/res_adsi.c
index 19fb713b2d..68793bf9f8 100644
--- a/res/res_adsi.c
+++ b/res/res_adsi.c
@@ -49,8 +49,6 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/module.h"
 #include "asterisk/config.h"
 #include "asterisk/file.h"
-
-#define AST_API_MODULE
 #include "asterisk/adsi.h"
 
 #define DEFAULT_ADSI_MAX_RETRIES 3
@@ -73,6 +71,35 @@ static char speeddial[ADSI_MAX_SPEED_DIAL][3][SPEEDDIAL_MAX_LEN];
 
 static int alignment = 0;
 
+static int adsi_begin_download(struct ast_channel *chan, char *service, unsigned char *fdn, unsigned char *sec, int version);
+static int adsi_end_download(struct ast_channel *chan);
+static int adsi_channel_restore(struct ast_channel *chan);
+static int adsi_print(struct ast_channel *chan, char **lines, int *align, int voice);
+static int adsi_load_session(struct ast_channel *chan, unsigned char *app, int ver, int data);
+static int adsi_unload_session(struct ast_channel *chan);
+static int adsi_transmit_message(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype);
+static int adsi_transmit_message_full(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype, int dowait);
+static int adsi_read_encoded_dtmf(struct ast_channel *chan, unsigned char *buf, int maxlen);
+static int adsi_connect_session(unsigned char *buf, unsigned char *fdn, int ver);
+static int adsi_query_cpeid(unsigned char *buf);
+static int adsi_query_cpeinfo(unsigned char *buf);
+static int adsi_get_cpeid(struct ast_channel *chan, unsigned char *cpeid, int voice);
+static int adsi_get_cpeinfo(struct ast_channel *chan, int *width, int *height, int *buttons, int voice);
+static int adsi_download_connect(unsigned char *buf, char *service, unsigned char *fdn, unsigned char *sec, int ver);
+static int adsi_disconnect_session(unsigned char *buf);
+static int adsi_download_disconnect(unsigned char *buf);
+static int adsi_data_mode(unsigned char *buf);
+static int adsi_clear_soft_keys(unsigned char *buf);
+static int adsi_clear_screen(unsigned char *buf);
+static int adsi_voice_mode(unsigned char *buf, int when);
+static int adsi_available(struct ast_channel *chan);
+static int adsi_display(unsigned char *buf, int page, int line, int just, int wrap, char *col1, char *col2);
+static int adsi_set_line(unsigned char *buf, int page, int line);
+static int adsi_load_soft_key(unsigned char *buf, int key, const char *llabel, const char *slabel, char *ret, int data);
+static int adsi_set_keys(unsigned char *buf, unsigned char *keys);
+static int adsi_input_control(unsigned char *buf, int page, int line, int display, int format, int just);
+static int adsi_input_format(unsigned char *buf, int num, int dir, int wrap, char *format1, char *format2);
+
 static int adsi_generate(unsigned char *buf, int msgtype, unsigned char *msg, int msglen, int msgnum, int last, struct ast_format *codec)
 {
 	int sum, x, bytes = 0;
@@ -328,7 +355,7 @@ static int __adsi_transmit_messages(struct ast_channel *chan, unsigned char **ms
 	return 0;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_begin_download)(struct ast_channel *chan, char *service, unsigned char *fdn, unsigned char *sec, int version)
+static int adsi_begin_download(struct ast_channel *chan, char *service, unsigned char *fdn, unsigned char *sec, int version)
 {
 	int bytes = 0;
 	unsigned char buf[256];
@@ -336,8 +363,8 @@ int AST_OPTIONAL_API_NAME(ast_adsi_begin_download)(struct ast_channel *chan, cha
 
 	/* Setup the resident soft key stuff, a piece at a time */
 	/* Upload what scripts we can for voicemail ahead of time */
-	bytes += ast_adsi_download_connect(buf + bytes, service, fdn, sec, version);
-	if (ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DOWNLOAD, 0)) {
+	bytes += adsi_download_connect(buf + bytes, service, fdn, sec, version);
+	if (adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DOWNLOAD, 0)) {
 		return -1;
 	}
 	if (ast_readstring(chan, ack, 1, 10000, 10000, "")) {
@@ -350,21 +377,21 @@ int AST_OPTIONAL_API_NAME(ast_adsi_begin_download)(struct ast_channel *chan, cha
 	return -1;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_end_download)(struct ast_channel *chan)
+static int adsi_end_download(struct ast_channel *chan)
 {
 	int bytes = 0;
 	unsigned char buf[256];
 
 	/* Setup the resident soft key stuff, a piece at a time */
 	/* Upload what scripts we can for voicemail ahead of time */
-	bytes += ast_adsi_download_disconnect(buf + bytes);
-	if (ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DOWNLOAD, 0)) {
+	bytes += adsi_download_disconnect(buf + bytes);
+	if (adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DOWNLOAD, 0)) {
 		return -1;
 	}
 	return 0;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_transmit_message_full)(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype, int dowait)
+static int adsi_transmit_message_full(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype, int dowait)
 {
 	unsigned char *msgs[5] = { NULL, NULL, NULL, NULL, NULL };
 	int msglens[5], msgtypes[5], newdatamode = (chan->adsicpe & ADSI_FLAG_DATAMODE), res, x, waitforswitch = 0;
@@ -440,9 +467,9 @@ int AST_OPTIONAL_API_NAME(ast_adsi_transmit_message_full)(struct ast_channel *ch
 	return res;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_transmit_message)(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype)
+static int adsi_transmit_message(struct ast_channel *chan, unsigned char *msg, int msglen, int msgtype)
 {
-	return ast_adsi_transmit_message_full(chan, msg, msglen, msgtype, 1);
+	return adsi_transmit_message_full(chan, msg, msglen, msgtype, 1);
 }
 
 static inline int ccopy(unsigned char *dst, const unsigned char *src, int max)
@@ -456,7 +483,7 @@ static inline int ccopy(unsigned char *dst, const unsigned char *src, int max)
 	return x;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_load_soft_key)(unsigned char *buf, int key, const char *llabel, const char *slabel, char *ret, int data)
+static int adsi_load_soft_key(unsigned char *buf, int key, const char *llabel, const char *slabel, char *ret, int data)
 {
 	int bytes = 0;
 
@@ -497,7 +524,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_load_soft_key)(unsigned char *buf, int key, c
 	return bytes;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_connect_session)(unsigned char *buf, unsigned char *fdn, int ver)
+static int adsi_connect_session(unsigned char *buf, unsigned char *fdn, int ver)
 {
 	int bytes = 0, x;
 
@@ -521,7 +548,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_connect_session)(unsigned char *buf, unsigned
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_download_connect)(unsigned char *buf, char *service,  unsigned char *fdn, unsigned char *sec, int ver)
+static int adsi_download_connect(unsigned char *buf, char *service,  unsigned char *fdn, unsigned char *sec, int ver)
 {
 	int bytes = 0, x;
 
@@ -553,7 +580,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_download_connect)(unsigned char *buf, char *s
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_disconnect_session)(unsigned char *buf)
+static int adsi_disconnect_session(unsigned char *buf)
 {
 	int bytes = 0;
 
@@ -568,7 +595,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_disconnect_session)(unsigned char *buf)
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_query_cpeid)(unsigned char *buf)
+static int adsi_query_cpeid(unsigned char *buf)
 {
 	int bytes = 0;
 	buf[bytes++] = ADSI_QUERY_CPEID;
@@ -578,7 +605,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_query_cpeid)(unsigned char *buf)
 	return bytes;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_query_cpeinfo)(unsigned char *buf)
+static int adsi_query_cpeinfo(unsigned char *buf)
 {
 	int bytes = 0;
 	buf[bytes++] = ADSI_QUERY_CONFIG;
@@ -588,7 +615,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_query_cpeinfo)(unsigned char *buf)
 	return bytes;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_read_encoded_dtmf)(struct ast_channel *chan, unsigned char *buf, int maxlen)
+static int adsi_read_encoded_dtmf(struct ast_channel *chan, unsigned char *buf, int maxlen)
 {
 	int bytes = 0, res, gotstar = 0, pos = 0;
 	unsigned char current = 0;
@@ -625,20 +652,20 @@ int AST_OPTIONAL_API_NAME(ast_adsi_read_encoded_dtmf)(struct ast_channel *chan,
 	return bytes;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_get_cpeid)(struct ast_channel *chan, unsigned char *cpeid, int voice)
+static int adsi_get_cpeid(struct ast_channel *chan, unsigned char *cpeid, int voice)
 {
 	unsigned char buf[256] = "";
 	int bytes = 0, res;
 
-	bytes += ast_adsi_data_mode(buf);
-	ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
+	bytes += adsi_data_mode(buf);
+	adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
 
 	bytes = 0;
-	bytes += ast_adsi_query_cpeid(buf);
-	ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
+	bytes += adsi_query_cpeid(buf);
+	adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
 
 	/* Get response */
-	res = ast_adsi_read_encoded_dtmf(chan, cpeid, 4);
+	res = adsi_read_encoded_dtmf(chan, cpeid, 4);
 	if (res != 4) {
 		ast_log(LOG_WARNING, "Got %d bytes back of encoded DTMF, expecting 4\n", res);
 		res = 0;
@@ -648,25 +675,25 @@ int AST_OPTIONAL_API_NAME(ast_adsi_get_cpeid)(struct ast_channel *chan, unsigned
 
 	if (voice) {
 		bytes = 0;
-		bytes += ast_adsi_voice_mode(buf, 0);
-		ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
+		bytes += adsi_voice_mode(buf, 0);
+		adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
 		/* Ignore the resulting DTMF B announcing it's in voice mode */
 		ast_waitfordigit(chan, 1000);
 	}
 	return res;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_get_cpeinfo)(struct ast_channel *chan, int *width, int *height, int *buttons, int voice)
+static int adsi_get_cpeinfo(struct ast_channel *chan, int *width, int *height, int *buttons, int voice)
 {
 	unsigned char buf[256] = "";
 	int bytes = 0, res;
 
-	bytes += ast_adsi_data_mode(buf);
-	ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
+	bytes += adsi_data_mode(buf);
+	adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
 
 	bytes = 0;
-	bytes += ast_adsi_query_cpeinfo(buf);
-	ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
+	bytes += adsi_query_cpeinfo(buf);
+	adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
 
 	/* Get width */
 	if ((res = ast_readstring(chan, (char *) buf, 2, 1000, 500, "")) < 0) {
@@ -715,15 +742,15 @@ int AST_OPTIONAL_API_NAME(ast_adsi_get_cpeinfo)(struct ast_channel *chan, int *w
 	}
 	if (voice) {
 		bytes = 0;
-		bytes += ast_adsi_voice_mode(buf, 0);
-		ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
+		bytes += adsi_voice_mode(buf, 0);
+		adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
 		/* Ignore the resulting DTMF B announcing it's in voice mode */
 		ast_waitfordigit(chan, 1000);
 	}
 	return res;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_data_mode)(unsigned char *buf)
+static int adsi_data_mode(unsigned char *buf)
 {
 	int bytes = 0;
 
@@ -738,7 +765,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_data_mode)(unsigned char *buf)
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_clear_soft_keys)(unsigned char *buf)
+static int adsi_clear_soft_keys(unsigned char *buf)
 {
 	int bytes = 0;
 
@@ -753,7 +780,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_clear_soft_keys)(unsigned char *buf)
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_clear_screen)(unsigned char *buf)
+static int adsi_clear_screen(unsigned char *buf)
 {
 	int bytes = 0;
 
@@ -768,7 +795,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_clear_screen)(unsigned char *buf)
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_voice_mode)(unsigned char *buf, int when)
+static int adsi_voice_mode(unsigned char *buf, int when)
 {
 	int bytes = 0;
 
@@ -785,7 +812,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_voice_mode)(unsigned char *buf, int when)
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_available)(struct ast_channel *chan)
+static int adsi_available(struct ast_channel *chan)
 {
 	int cpe = chan->adsicpe & 0xff;
 	if ((cpe == AST_ADSI_AVAILABLE) ||
@@ -795,7 +822,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_available)(struct ast_channel *chan)
 	return 0;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_download_disconnect)(unsigned char *buf)
+static int adsi_download_disconnect(unsigned char *buf)
 {
 	int bytes = 0;
 
@@ -810,7 +837,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_download_disconnect)(unsigned char *buf)
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_display)(unsigned char *buf, int page, int line, int just, int wrap,
+static int adsi_display(unsigned char *buf, int page, int line, int just, int wrap,
 		 char *col1, char *col2)
 {
 	int bytes = 0;
@@ -857,7 +884,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_display)(unsigned char *buf, int page, int li
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_input_control)(unsigned char *buf, int page, int line, int display, int format, int just)
+static int adsi_input_control(unsigned char *buf, int page, int line, int display, int format, int just)
 {
 	int bytes = 0;
 
@@ -880,7 +907,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_input_control)(unsigned char *buf, int page,
 	return bytes;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_input_format)(unsigned char *buf, int num, int dir, int wrap, char *format1, char *format2)
+static int adsi_input_format(unsigned char *buf, int num, int dir, int wrap, char *format1, char *format2)
 {
 	int bytes = 0;
 
@@ -900,7 +927,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_input_format)(unsigned char *buf, int num, in
 	return bytes;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_set_keys)(unsigned char *buf, unsigned char *keys)
+static int adsi_set_keys(unsigned char *buf, unsigned char *keys)
 {
 	int bytes = 0, x;
 
@@ -916,7 +943,7 @@ int AST_OPTIONAL_API_NAME(ast_adsi_set_keys)(unsigned char *buf, unsigned char *
 	return bytes;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_set_line)(unsigned char *buf, int page, int line)
+static int adsi_set_line(unsigned char *buf, int page, int line)
 {
 	int bytes = 0;
 
@@ -947,14 +974,14 @@ int AST_OPTIONAL_API_NAME(ast_adsi_set_line)(unsigned char *buf, int page, int l
 static int total = 0;
 static int speeds = 0;
 
-int AST_OPTIONAL_API_NAME(ast_adsi_channel_restore)(struct ast_channel *chan)
+static int adsi_channel_restore(struct ast_channel *chan)
 {
 	unsigned char dsp[256] = "", keyd[6] = "";
 	int bytes, x;
 
 	/* Start with initial display setup */
 	bytes = 0;
-	bytes += ast_adsi_set_line(dsp + bytes, ADSI_INFO_PAGE, 1);
+	bytes += adsi_set_line(dsp + bytes, ADSI_INFO_PAGE, 1);
 
 	/* Prepare key setup messages */
 
@@ -962,26 +989,26 @@ int AST_OPTIONAL_API_NAME(ast_adsi_channel_restore)(struct ast_channel *chan)
 		for (x = 0; x < speeds; x++) {
 			keyd[x] = ADSI_SPEED_DIAL + x;
 		}
-		bytes += ast_adsi_set_keys(dsp + bytes, keyd);
+		bytes += adsi_set_keys(dsp + bytes, keyd);
 	}
-	ast_adsi_transmit_message_full(chan, dsp, bytes, ADSI_MSG_DISPLAY, 0);
+	adsi_transmit_message_full(chan, dsp, bytes, ADSI_MSG_DISPLAY, 0);
 	return 0;
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_print)(struct ast_channel *chan, char **lines, int *alignments, int voice)
+static int adsi_print(struct ast_channel *chan, char **lines, int *alignments, int voice)
 {
 	unsigned char buf[4096];
 	int bytes = 0, res, x;
 
 	for (x = 0; lines[x]; x++) {
-		bytes += ast_adsi_display(buf + bytes, ADSI_INFO_PAGE, x+1, alignments[x], 0, lines[x], "");
+		bytes += adsi_display(buf + bytes, ADSI_INFO_PAGE, x+1, alignments[x], 0, lines[x], "");
 	}
-	bytes += ast_adsi_set_line(buf + bytes, ADSI_INFO_PAGE, 1);
+	bytes += adsi_set_line(buf + bytes, ADSI_INFO_PAGE, 1);
 	if (voice) {
-		bytes += ast_adsi_voice_mode(buf + bytes, 0);
+		bytes += adsi_voice_mode(buf + bytes, 0);
 	}
-	res = ast_adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
+	res = adsi_transmit_message_full(chan, buf, bytes, ADSI_MSG_DISPLAY, 0);
 	if (voice) {
 		/* Ignore the resulting DTMF B announcing it's in voice mode */
 		ast_waitfordigit(chan, 1000);
@@ -989,21 +1016,21 @@ int AST_OPTIONAL_API_NAME(ast_adsi_print)(struct ast_channel *chan, char **lines
 	return res;
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_load_session)(struct ast_channel *chan, unsigned char *app, int ver, int data)
+static int adsi_load_session(struct ast_channel *chan, unsigned char *app, int ver, int data)
 {
 	unsigned char dsp[256] = "";
 	int bytes = 0, res;
 	char resp[2];
 
 	/* Connect to session */
-	bytes += ast_adsi_connect_session(dsp + bytes, app, ver);
+	bytes += adsi_connect_session(dsp + bytes, app, ver);
 
 	if (data) {
-		bytes += ast_adsi_data_mode(dsp + bytes);
+		bytes += adsi_data_mode(dsp + bytes);
 	}
 
 	/* Prepare key setup messages */
-	if (ast_adsi_transmit_message_full(chan, dsp, bytes, ADSI_MSG_DISPLAY, 0)) {
+	if (adsi_transmit_message_full(chan, dsp, bytes, ADSI_MSG_DISPLAY, 0)) {
 		return -1;
 	}
 	if (app) {
@@ -1028,17 +1055,17 @@ int AST_OPTIONAL_API_NAME(ast_adsi_load_session)(struct ast_channel *chan, unsig
 
 }
 
-int AST_OPTIONAL_API_NAME(ast_adsi_unload_session)(struct ast_channel *chan)
+static int adsi_unload_session(struct ast_channel *chan)
 {
 	unsigned char dsp[256] = "";
 	int bytes = 0;
 
 	/* Connect to session */
-	bytes += ast_adsi_disconnect_session(dsp + bytes);
-	bytes += ast_adsi_voice_mode(dsp + bytes, 0);
+	bytes += adsi_disconnect_session(dsp + bytes);
+	bytes += adsi_voice_mode(dsp + bytes, 0);
 
 	/* Prepare key setup messages */
-	if (ast_adsi_transmit_message_full(chan, dsp, bytes, ADSI_MSG_DISPLAY, 0)) {
+	if (adsi_transmit_message_full(chan, dsp, bytes, ADSI_MSG_DISPLAY, 0)) {
 		return -1;
 	}
 
@@ -1140,19 +1167,53 @@ static int reload(void)
 	return 0;
 }
 
+static struct adsi_funcs res_adsi_funcs = {
+	.version = AST_ADSI_VERSION,
+	.begin_download = adsi_begin_download,
+	.end_download = adsi_end_download,
+	.channel_restore = adsi_channel_restore,
+	.print = adsi_print,
+	.load_session = adsi_load_session,
+	.unload_session = adsi_unload_session,
+	.transmit_message = adsi_transmit_message,
+	.transmit_message_full = adsi_transmit_message_full,
+	.read_encoded_dtmf = adsi_read_encoded_dtmf,
+	.connect_session = adsi_connect_session,
+	.query_cpeid = adsi_query_cpeid,
+	.query_cpeinfo = adsi_query_cpeinfo,
+	.get_cpeid = adsi_get_cpeid,
+	.get_cpeinfo = adsi_get_cpeinfo,
+	.download_connect = adsi_download_connect,
+	.disconnect_session = adsi_disconnect_session,
+	.download_disconnect = adsi_download_disconnect,
+	.data_mode = adsi_data_mode,
+	.clear_soft_keys = adsi_clear_soft_keys,
+	.clear_screen = adsi_clear_screen,
+	.voice_mode = adsi_voice_mode,
+	.available = adsi_available,
+	.display = adsi_display,
+	.set_line = adsi_set_line,
+	.load_soft_key = adsi_load_soft_key,
+	.set_keys = adsi_set_keys,
+	.input_control = adsi_input_control,
+	.input_format = adsi_input_format,
+};
+
 static int load_module(void)
 {
 	adsi_load(0);
+	ast_adsi_install_funcs(&res_adsi_funcs);
 	return AST_MODULE_LOAD_SUCCESS;
 }
 
 static int unload_module(void)
 {
 	/* Can't unload this once we're loaded */
+	ast_adsi_install_funcs(NULL);
 	return -1;
 }
 
-AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "ADSI Resource",
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "ADSI Resource",
 		.load = load_module,
 		.unload = unload_module,
 		.reload = reload,
diff --git a/res/res_adsi.exports.in b/res/res_adsi.exports.in
deleted file mode 100644
index fd7527b368..0000000000
--- a/res/res_adsi.exports.in
+++ /dev/null
@@ -1,33 +0,0 @@
-{
-	global:
-		LINKER_SYMBOL_PREFIX*ast_adsi_available;
-		LINKER_SYMBOL_PREFIX*ast_adsi_begin_download;
-		LINKER_SYMBOL_PREFIX*ast_adsi_channel_restore;
-		LINKER_SYMBOL_PREFIX*ast_adsi_clear_screen;
-		LINKER_SYMBOL_PREFIX*ast_adsi_clear_soft_keys;
-		LINKER_SYMBOL_PREFIX*ast_adsi_connect_session;
-		LINKER_SYMBOL_PREFIX*ast_adsi_data_mode;
-		LINKER_SYMBOL_PREFIX*ast_adsi_disconnect_session;
-		LINKER_SYMBOL_PREFIX*ast_adsi_display;
-		LINKER_SYMBOL_PREFIX*ast_adsi_download_connect;
-		LINKER_SYMBOL_PREFIX*ast_adsi_download_disconnect;
-		LINKER_SYMBOL_PREFIX*ast_adsi_end_download;
-		LINKER_SYMBOL_PREFIX*ast_adsi_get_cpeid;
-		LINKER_SYMBOL_PREFIX*ast_adsi_get_cpeinfo;
-		LINKER_SYMBOL_PREFIX*ast_adsi_input_control;
-		LINKER_SYMBOL_PREFIX*ast_adsi_input_format;
-		LINKER_SYMBOL_PREFIX*ast_adsi_load_session;
-		LINKER_SYMBOL_PREFIX*ast_adsi_load_soft_key;
-		LINKER_SYMBOL_PREFIX*ast_adsi_print;
-		LINKER_SYMBOL_PREFIX*ast_adsi_query_cpeid;
-		LINKER_SYMBOL_PREFIX*ast_adsi_query_cpeinfo;
-		LINKER_SYMBOL_PREFIX*ast_adsi_read_encoded_dtmf;
-		LINKER_SYMBOL_PREFIX*ast_adsi_set_keys;
-		LINKER_SYMBOL_PREFIX*ast_adsi_set_line;
-		LINKER_SYMBOL_PREFIX*ast_adsi_transmit_message;
-		LINKER_SYMBOL_PREFIX*ast_adsi_transmit_message_full;
-		LINKER_SYMBOL_PREFIX*ast_adsi_unload_session;
-		LINKER_SYMBOL_PREFIX*ast_adsi_voice_mode;
-	local:
-		*;
-};