diff --git a/tools/include/misctxrx.h b/tools/include/misctxrx.h
index 9d258bb..7e531ad 100644
--- a/tools/include/misctxrx.h
+++ b/tools/include/misctxrx.h
@@ -19,6 +19,14 @@
 
 
 void flush_interrupts(struct atrf_dsc *dsc);
+
+/*
+ * timeout_ms:
+ * > 0:   time out after that many milliseconds
+ * == 0:  wait forever
+ * < 0:   wait forever and eliminate poll delays (for high-speed capture)
+ */
+
 uint8_t wait_for_interrupt(struct atrf_dsc *dsc, uint8_t wait_for,
     uint8_t ignore, int timeout_ms);
 
diff --git a/tools/lib/atben.c b/tools/lib/atben.c
index 4230633..22abecc 100644
--- a/tools/lib/atben.c
+++ b/tools/lib/atben.c
@@ -1,8 +1,8 @@
 /*
  * lib/atben.c - ATRF access functions library (Ben 8:10 card version)
  *
- * Written 2010-2011 by Werner Almesberger
- * Copyright 2010-2011 Werner Almesberger
+ * Written 2010-2011, 2013 by Werner Almesberger
+ * Copyright 2010-2011, 2013 Werner Almesberger
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -439,10 +439,10 @@ int atben_interrupt_wait(void *handle, int timeout_ms)
 	int timedout = 0;
 	uint8_t irq;
 
-	if (timeout_ms)
+	if (timeout_ms > 0)
 		timeout_start(&to, timeout_ms);
 	while (1) {
-		if (timeout_ms)
+		if (timeout_ms > 0)
 			timedout = timeout_reached(&to);
 		if (atben_interrupt(handle)) {
 			irq = atben_reg_read(handle, REG_IRQ_STATUS);
@@ -452,7 +452,8 @@ int atben_interrupt_wait(void *handle, int timeout_ms)
 		}
 		if (timedout)
 			return 0;
-		usleep(1000);
+		if (timeout_ms >= 0)
+			usleep(1000);
 	}
 
 	return 0;
diff --git a/tools/lib/atusb-common.c b/tools/lib/atusb-common.c
index d43a168..2d9b15a 100644
--- a/tools/lib/atusb-common.c
+++ b/tools/lib/atusb-common.c
@@ -221,7 +221,7 @@ int atusb_interrupt_wait(void *handle, int timeout_ms)
 		return 0;
 
 	res = usb_bulk_read(dsc->dev, 1,
-	    (char *) &buf, sizeof(buf), timeout_ms);
+	    (char *) &buf, sizeof(buf), timeout_ms < 0 : 0 : timeout_ms);
 	if (res == -ETIMEDOUT)
 		return 0;
 	if (res < 0) {
diff --git a/tools/lib/misctxrx.c b/tools/lib/misctxrx.c
index 2b46e9a..820ad00 100644
--- a/tools/lib/misctxrx.c
+++ b/tools/lib/misctxrx.c
@@ -62,14 +62,14 @@ uint8_t wait_for_interrupt(struct atrf_dsc *dsc, uint8_t wait_for,
 
 	sigint = 0;
 	old_sig = signal(SIGINT, die);
-	if (timeout_ms) {
+	if (timeout_ms > 0) {
 		if (timeout_ms < MIN_TIMEOUT_MS)
 			timeout_ms = MIN_TIMEOUT_MS;
 		timeout_start(&to, timeout_ms);
 	}
 	while (!sigint && !timedout) {
 		while (!sigint && !timedout) {
-			if (timeout_ms) {
+			if (timeout_ms > 0) {
 				ms = timeout_left_ms(&to);
 				if (ms <= 0) {
 					timedout = 1;
@@ -78,7 +78,8 @@ uint8_t wait_for_interrupt(struct atrf_dsc *dsc, uint8_t wait_for,
 			} else {
 				ms = 0;
 			}
-			irq = atrf_interrupt_wait(dsc, ms);
+			irq = atrf_interrupt_wait(dsc,
+			    timeout_ms < 0 ? -1 : ms);
 			if (irq)
 				break;
 		}