ZETRON 2000 Series Especificaciones descargar pdf (Pagina 145)

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TNPP Link Tips - UDS 202T and Leased Line

Place both modems into the DATA mode by turning the switch to the DATA position.

Within a second, both modems should carrier lock, shown by the lighting of their CD

LEDs. Once this has been verified, confirm that carrier loss can be detected. Do this by

switching one of the modems to the TALK mode - the other modem's CD LED should go

dark. Placing the modem back in DATA mode will reestablish CD at the other modem.

If switching one modem to TALK mode does not extinguish the CD LED on the other

modem, then either the second modem, in DATA mode, has its carrier detect sensitivity

set too high, or the second modem is “hearing” itself for some other reason. This could be

excessive cross talk on the telephone lines or a wiring problem in connecting the modems

to the 4-wire line.

Next, place one of the modems in the Test Pattern mode by moving its switch to the TTP

position. The other modem should have its MR/RI, TR, and CD LED steady on, and its

RD LED flashing or flickering mostly on. Place the first modem back in DATA mode and

repeat the test for the second modem by placing it in the TTP mode. See the 202T manual

for more information on the Test Pattern mode.

If the above tests were successful, it should be possible to establish the TNPP link.

Connect the modems to the TNPP serial ports. Check that both modems are in DATA

mode and that their CD LEDs are on.

If there are problems in establishing the TNPP link, some simple fault isolation may be

performed. This can help in pointing out if the problem lies in the TNPP card and its serial

cable connection to the modem, or in the modems or telephone line.

If a modem is placed in the AL (analog loopback) mode, then the TNPP card connected to

the modem is “talking to itself”. Within 20 seconds, it should indicate a link-up state by

fully lighting the CHAN LED for the modem connection. It is not likely that TNPP

packets will properly transmit, as the terminal is most likely not programmed to “hear”

packets that it transmits. However, the link should remain up, indicating that the TNPP

card, the serial cable connections, and most of the modem are functional. The other

modem should have indicated loss of carrier by turning off its CD LED.

If one modem is in DATA mode and the other modem is switched to DL (digital

loopback) mode, then the telephone line and both modems can be checked. When in this

state, the modem in DATA mode should have its CD LED on. The TNPP card connected

to the modem in DATA mode should enter the link-up state within 20 seconds. If it does

so, this shows that the TNPP card, both modems, and the telephone line are functioning.

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ZETRON 2000 Series Especificaciones Pagina 145