Index: uspace/app/tmon/Makefile
===================================================================
--- uspace/app/tmon/Makefile	(revision 73b0773c31969fd83f88107b0deb13625c49217b)
+++ uspace/app/tmon/Makefile	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
@@ -13,5 +13,5 @@
 #   documentation and/or other materials provided with the distribution.
 # - The name of the author may not be used to endorse or promote products
-#   derived from this software without specific prior written permission.
+#   derived from thgis software without specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
@@ -34,5 +34,6 @@
 SOURCES = \
 	main.c\
-	list.c
+	list.c\
+	test.c
 
 include $(USPACE_PREFIX)/Makefile.common
Index: uspace/app/tmon/commands.h
===================================================================
--- uspace/app/tmon/commands.h	(revision 73b0773c31969fd83f88107b0deb13625c49217b)
+++ uspace/app/tmon/commands.h	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
@@ -38,4 +38,5 @@
 
 int tmon_list(int, char **);
+int tmon_test_bulk(int, char **);
 
 #endif /* TMON_COMMANDS_H_ */
Index: uspace/app/tmon/list.c
===================================================================
--- uspace/app/tmon/list.c	(revision 73b0773c31969fd83f88107b0deb13625c49217b)
+++ uspace/app/tmon/list.c	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
@@ -71,5 +71,5 @@
 
 	if ((rc = loc_category_get_svcs(diag_cat, &svcs, &count))) {
-		printf(NAME ": Error getting list of host controllers.\n");
+		printf(NAME ": Error getting list of diagnostic devices.\n");
 		return 1;
 	}
Index: uspace/app/tmon/main.c
===================================================================
--- uspace/app/tmon/main.c	(revision 73b0773c31969fd83f88107b0deb13625c49217b)
+++ uspace/app/tmon/main.c	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
@@ -56,4 +56,8 @@
 	},
 	{
+		.name = "test-bulk",
+		.action = tmon_test_bulk,
+	},
+	{
 		.name = NULL
 	}
Index: uspace/app/tmon/test.c
===================================================================
--- uspace/app/tmon/test.c	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
+++ uspace/app/tmon/test.c	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2017 Petr Manek
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup tmon
+ * @{
+ */
+/**
+ * @file
+ * USB transfer debugging.
+ */
+
+#include <stdio.h>
+#include <devman.h>
+#include <loc.h>
+#include <errno.h>
+#include <str_error.h>
+#include <usb/diag/diag.h>
+#include "commands.h"
+
+#define NAME "tmon"
+
+static int resolve_default_fun(devman_handle_t *fun)
+{
+	category_id_t diag_cat;
+	service_id_t *svcs;
+	size_t count;
+	int rc;
+
+	if ((rc = loc_category_get_id(USB_DIAG_CATEGORY, &diag_cat, 0))) {
+		printf(NAME ": Error resolving category '%s'", USB_DIAG_CATEGORY);
+		return rc;
+	}
+
+	if ((rc = loc_category_get_svcs(diag_cat, &svcs, &count))) {
+		printf(NAME ": Error getting list of diagnostic devices.\n");
+		return rc;
+	}
+
+	// There must be exactly one diagnostic device for this to work.
+	if (count != 1) {
+		if (count) {
+			printf(NAME ": Found %ld devices. Please specify which to use.\n", count);
+		} else {
+			printf(NAME ": No diagnostic devices found.\n");
+		}
+		return ENOENT;
+	}
+
+	if ((rc = devman_fun_sid_to_handle(svcs[0], fun))) {
+		printf(NAME ": Error resolving handle of device with SID %ld.\n", svcs[0]);
+		return rc;
+	}
+
+	return EOK;
+}
+
+static int resolve_named_fun(const char *dev_path, devman_handle_t *fun)
+{
+	int rc;
+	service_id_t svc;
+	if ((rc = loc_service_get_id(dev_path, &svc, IPC_FLAG_BLOCKING))) {
+		printf(NAME ": Error resolving device. %s\n", str_error(rc));
+		return rc;
+	}
+
+	if ((rc = devman_fun_sid_to_handle(svc, fun))) {
+		printf(NAME ": Error resolving handle of device with SID %ld.\n", svc);
+		return rc;
+	}
+
+	return EOK;
+}
+
+static int resolve_and_test(int argc, char *argv[], int (*test)(devman_handle_t)) {
+	devman_handle_t fun = -1;
+
+	if (argc == 0) {
+		if (resolve_default_fun(&fun))
+			return 1;
+	} else if (argc == 1) {
+		if (resolve_named_fun(argv[0], &fun))
+			return 1;
+	} else {
+		printf(NAME ": Too many arguments provided.\n");
+		return 1;
+	}
+
+	return test(fun);
+}
+
+static int bulk_worker(devman_handle_t fun) {
+	// TODO: do some testing
+	return 0;
+}
+
+int tmon_test_bulk(int argc, char *argv[])
+{
+	return resolve_and_test(argc, argv, bulk_worker);
+}
+
+/** @}
+ */