Multi-Tech Systems MT202TD 1200 manual Digital Loopback Test, Modem Testing

Chapter 3 - Modem Testing

2 for DIP switch setting information).

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Computer or Terminal Local MultiModem

Figure 3-3. Local Analog Loopback Test

Digital Loopback Test

The digital loopback test is an on-line test that loops data sent from one modem across the phone line to another modem, and then back to the first modem. This test checks the phone line and modem integrity.

This digital loopback test is used on modems configured for four-wire leased lines. To perform this test, the DLB switch on the modem’s circuit board must be set to the DLB position (see Figure 2-3 in Chapter 2).

In this test the local modem is placed in digital loopback mode. Data is entered and transmitted from the remote modem (which is not in digital loopback mode), sent across the phone line to the local modem, and looped back to the remote modem.

OK

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Computer or Terminal Local MultiModem Remote MultiModem Computer or Terminal

Figure 3-4. Digital Loopback Test

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