ADTRAN 25 manual

6.If +7 volts are not present, the ADU is not receiving enough power from the data terminal and must be locally powered.

7.If the ADU is powered from a local transformer, make sure that a 3- pair or 2-pair modular cord is connected between the transformer and the ADU.

8.Using a 4-pair modular jack breakout box, check to be sure that the ac voltage between pins 7 and 8 is about 14 volts under load or about 28 volts for an open circuit.

9.Even with alternate power, the data terminal needs to deliver at least 3 volts on pin 20 (DTR signal).

10.Check the data terminal settings that have been administered at the SAT to be sure that the administered settings match those of the data terminal. Settings should be for 8 bits, no parity with O in the parity bit. Check the baud rate settings. Even if the terminal accommodates autobaud rate, the administered settings must include the baud rate.

11.If the data port is administered for “long break” disconnects, check to be sure that breaks from the terminal are at least 2 seconds. If they are not, or if the break length cannot be determined, insert a device with a disconnect button in the line and enter 2-second b r e a k s .

12.Check wiring.

13.If none of the preceding procedures correct the terminal troubles, change the ADU.

14.If the problems persist, replace the Data Line CP.

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