Index: uspace/app/test_serial/test_serial.c
===================================================================
--- uspace/app/test_serial/test_serial.c	(revision ba95e8f41817124410b7cfa7c805434f83686dff)
+++ uspace/app/test_serial/test_serial.c	(revision ca97cad5803ad9a8511c331f8c9583385867b64d)
@@ -45,4 +45,5 @@
 #include <devman.h>
 #include <device/char.h>
+#include <string.h>
 
 #define NAME 		"test serial"
@@ -104,9 +105,14 @@
 		if (read > 0) {			
 			buf[read] = 0;
-			printf(buf);		
+			printf(buf);	
+			// write data back to the device to test the opposite direction of data transfer
+			write_dev(phone, buf, read);
 		} else {	
 			usleep(100000);			
 		}	
 	}
+	
+	char *the_end = "\n---------\nTHE END\n---------\n";
+	write_dev(phone, the_end, str_size(the_end));
 	
 	devman_hangup_phone(DEVMAN_CLIENT);