--- ../asterisk-1.4.11/channels/chan_iax2.c     2007-08-17 09:29:24.000000000 +1200
+++ channels/chan_iax2.c        2007-09-23 22:13:38.000000000 +1200
@@ -494,6 +494,8 @@
        struct ast_codec_pref prefs;
        /*! Requested codec preferences */
        struct ast_codec_pref rprefs;
+       /*! Timestamp smoother */
+       struct ast_smoother *smoother;
        /*! Our call number */
        unsigned short callno;
        /*! Peer callno */
@@ -4662,10 +4664,21 @@
 static int iax2_write(struct ast_channel *c, struct ast_frame *f)
 {
        unsigned short callno = PTR_TO_CALLNO(c->tech_pvt);
+       struct chan_iax2_pvt *p = iaxs[callno];
        int res = -1;
+       int alaw_or_ulaw = 0;
        ast_mutex_lock(&iaxsl[callno]);
        if (iaxs[callno]) {
-       /* If there's an outstanding error, return failure now */
+               if (c->readformat & AST_FORMAT_ULAW || c->readformat & AST_FORMAT_ALAW ) {
+                       alaw_or_ulaw = 1;
+                       if (!p->smoother) {
+                               p->smoother = ast_smoother_new(160);
+                               if (!p->smoother)
+                                       return 0;
+                       }
+                       ast_smoother_feed(p->smoother, f);
+               }
+               /* If there's an outstanding error, return failure now */
                if (!iaxs[callno]->error) {
                        if (ast_test_flag(iaxs[callno], IAX_ALREADYGONE))
                                res = 0;
@@ -4676,9 +4689,17 @@
                                res = 0;
                        else if (!ast_test_flag(&iaxs[callno]->state, IAX_STATE_STARTED))
                                res = 0;
-                       else
-                       /* Simple, just queue for transmission */
-                               res = iax2_send(iaxs[callno], f, 0, -1, 0, 0, 0);
+                       else {
+                               if (!alaw_or_ulaw) {
+                                       /* Simple, just queue for transmission */
+                                       res = iax2_send(iaxs[callno], f, 0, -1, 0, 0, 0);
+                               } else {
+                                       res = 1; /* we might still be filling the smoother */
+                                       while ((f = ast_smoother_read(p->smoother)) && f->data) {
+                                               res = iax2_send(iaxs[callno], f, 0, -1, 0, 0, 0);
+                                       }
+                               }
+                       }
                } else {
                        ast_log(LOG_DEBUG, "Write error: %s\n", strerror(errno));
                }