MT202TD User Guide
Chapter 3 - Modem Testing
Introduction
The MT202TD has two diagnostic tests: Local analog loopback and digital loopback.
A loopback test involves entering data from your PC and looping that data through the circuits of your modem and/or a remote modem. When the loop has been completed, the data received on the monitor should match the data entered on the keyboard.
The local analog loopback test allows you to verify that the modem’s transmit and receive circuits are functioning properly. Refer to the Local Analog Loopback section on the following page for more details.
The digital loopback test allows you to verify that the local computer or terminal, the two modems, and the transmission line between the devices are functioning properly. See the Digital Loopback Test section in this chapter for more information.
Local Analog Loopback Test
The analog loopback test is performed by placing the analog loopback (ALB) switch in the ALB position (see Figure
In this test, data from your computer or terminal is sent to your modem’s transmitter, converted into analog form, looped back to the receiver, converted into digital form, and then received back at your monitor for verification. No connection to the phone line is required. The TD and RD indicators blink as keys are pressed. If your modem is configured for
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