--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rvinterf/lowlevel/tchhide.c	Mon Dec 12 22:15:25 2022 +0000
@@ -0,0 +1,50 @@
+/*
+ * One of several FreeCalypso extensions to RVTMUX is TCH bit access
+ * logical channel, and we would like to handle it specially in rvinterf
+ * because it's extremely chatty, sending a frame every 20 ms.  If we
+ * were to output every TCH frame in our regular log, that log output
+ * becomes useless as everything else is drowned out.  Therefore, we
+ * implement a hiding mode by default: we only count how many TCH packets
+ * were exchanged in between other messages of interest, and report these
+ * counts.
+ */
+
+#include <stdio.h>
+
+extern void (*output_hook)();
+
+unsigned tch_rx_count, tch_tx_count;
+
+static void
+tch_report_hook()
+{
+	char msgbuf[80];
+
+	output_hook = 0;
+	if (tch_rx_count) {
+		sprintf(msgbuf, "TCH: received %u packet%s", tch_rx_count,
+			tch_rx_count != 1 ? "s" : "");
+		output_line(msgbuf);
+		tch_rx_count = 0;
+	}
+	if (tch_tx_count) {
+		sprintf(msgbuf, "TCH: sent %u packet%s", tch_tx_count,
+			tch_tx_count != 1 ? "s" : "");
+		output_line(msgbuf);
+		tch_tx_count = 0;
+	}
+}
+
+void
+tch_inc_count_rx()
+{
+	tch_rx_count++;
+	output_hook = tch_report_hook;
+}
+
+void
+tch_inc_count_tx()
+{
+	tch_tx_count++;
+	output_hook = tch_report_hook;
+}