User`s manual

U.S. Robotics I-modem Command Reference
Testing • Page 14-2
Testing the I-modem (Using &T)
Perform digital loopback and remote digital loopback testing by using the &T command.
You can type in your own data during testing or use the I-modem's internal test pattern and
error detector.
Note Disable error control (using the &M0 command) before testing. If the I-
modem is detecting errors and retransmitting the affected data, your results
will be invalid.
Digital Loopback Testing (&T3)
This test can help you locate a problem with a remote device or with the tele-phone line.
Figure 14-1 shows the data ßow during digital loopback testing.
Figure 14-1. Data Flow During Digital Loopback