User`s manual

U.S. Robotics I-modem Command Reference
Testing • Page 14-5
Remote Digital Loopback Testing (&T6, &T7)
This test, like the local digital loopback test, veriÞes the condition of both devices and of
the phone line. Data ßow is shown in Figure 14-2.
Figure 14-2. Data Flow During Remote Digital Loopback
The request for and granting of remote digital loopback testing requires that both devices
use ITU-T V.22 standard signaling. If the remote device does not have the capability or is
not set to respond (with &T4), you will get an ERROR result code.
There are two remote digi-tal loopback options. If you select &T6, you send keyboard data
to the I-modem and verify it when it is returned over the phone lines and to your screen. If
you select &T7, the I-modem sends its internal test pattern and returns an error count to
your screen.