--- a/test-fsk/main.c	Mon Mar 04 21:22:27 2024 -0800
+++ b/test-fsk/main.c	Mon Mar 04 22:08:19 2024 -0800
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <strings.h>
 #include <unistd.h>
+#include <spandsp.h>
 #include "../libsip/out_msg.h"
 #include "../libsip/sdp.h"
 
@@ -30,6 +31,7 @@
 unsigned max_forwards = 70;
 int declare_100rel_supp;
 int pcma_codec_pref, pcma_codec_force;
+int fsk_mode_rx, fsk_mode_tx;
 
 send_invite_req()
 {
@@ -75,6 +77,23 @@
 }
 
 static void
+select_modulation(modname)
+	char *modname;
+{
+	if (!strcmp(modname, "v21")) {
+		fsk_mode_rx = FSK_V21CH2;
+		fsk_mode_tx = FSK_V21CH1;
+	} else if (!strcmp(modname, "bell103")) {
+		fsk_mode_rx = FSK_BELL103CH2;
+		fsk_mode_tx = FSK_BELL103CH1;
+	} else {
+		fprintf(stderr, "error: modulation name \"%s\" unknown\n",
+			modname);
+		exit(1);
+	}
+}
+
+static void
 preliminary_proc(argc, argv)
 	char **argv;
 {
@@ -104,12 +123,12 @@
 		default:
 		usage:
 			fprintf(stderr,
-			"usage: %s [options] dest-conf from-num to-num\n",
+			"usage: %s [options] dest-conf from-num to-num mode\n",
 				argv[0]);
 			exit(1);
 		}
 	}
-	if (argc != optind + 3)
+	if (argc != optind + 4)
 		goto usage;
 	read_config_file(argv[optind]);
 	open_sip_udp_socket();
@@ -120,6 +139,7 @@
 	sprintf(from_uri, "<sip:%s@%s>;tag=out%u", argv[optind+1],
 		inet_ntoa(sip_bind_ip), ntohs(rtp_local_addr.sin_port));
 	sprintf(to_uri, "sip:%s@%s", argv[optind+2], sip_dest_domain);
+	select_modulation(argv[optind+3]);
 	if (logfile) {
 		rc = open_sip_log_file(logfile);
 		if (rc < 0)