3902 Digital phone random ringing

[leekawai]

I have two 3902 phones in a system which will have few second of ringing but it's display does not change at all. These two phones are located very closely. This problem kept occurring in a random period (from 4min to 10 min). Enhanced trace in LD 80 shows no change of the phone state during the problem . This problem has been stopped for a month after change of wiring in the connecting box. But now it happens again. Any idea ??

 

[dapster1]

I have read this post
Change tn ports as a start or replace digial
Line card. verify 3902 sets by replacing them
I used 3902 sets in a utility setting and they did some strange things
Good luck

 

[Firebird Scrambler]

You might need to change the polarity of the wires and also check that the TN for each set is configured correctly with the right phone type of M3902.

Check the ringing key is SCR or MCR and that CLS = CNDA