sundance-communications.com/forum Forums TDM Business Telephone Systems NEC Telephones & Systems NEC DSX 40 ANAlog ports 325 and 326

Hey guys I am trying to hook my fax machine to port 326 on my dsx 40 but when i go off hook all i get is a busy signal. If i intercom 326 from a phone it works fine but when i go off hook to try and fax out i do not get any dial tone all i get is a busy signal can any one guide me I have SIP trunks and 1 copper trunk I can not figure what the issue could be that is causiong this any help would be greatly appreciated.

What is your prime line in 2114 set to? I would set it to the specific line you want to use for the fax or set it to a line group. Also, does that station have access to the line or group that you want to use in 2131 or 2133?

I got it figured out a little bit ago it was due to my SIP lines and I had to set it for line group 92. but now for some reason when i receive a fax it says receive failed I dont understand why it is failing

Here is an update i checked the 3 programs and I have them all set now when i get a incomming fax it says receive failed any ideas on what i can try next the call is routing to the fax now but it is not staying connected long enough to receive the fax any help would be great

Yes, check your wiring coming out of the DSX.
You probably have a split pair of the 2 extensions.

Fax and SIP are generally not a good mix. You need the t.38 protocol, but it doesn't seem to be an option on the DSX. You may get by with G.711 but it probably wont be reliable.

Ok i have my calls are being answered by my AA and it is routing the call to my fax ext 326 for some reason when it connects it still says received failed i was wondering if it might have something to do with the length of time from the AA to the transfer to the fax ext. I am at a loss as to why it is doing this. I have never seen this before and do not have a clue why it is failing like it is.

Try temporarily ringing the trunk straight to the fax extension to see if it works end to end without timing coming Into play.

I guess it's the copper trunk you are using for fax

If i intercom it from 301 it works fine and like i say i can have someone send a fax and i can watch it the system answer and watch it transfer to fax and then all i get is received failed. When i had it going through my fax stick it worked fine never any issues i just went full auto at the office and knew i could use a analog port for the fax and it should work but it is not working so I guess i will call DSX support tomorrow if i can not figure it out.

With it working before with no issues i was thinking that it might have been a timing issue but now I am not sure I hope i can get it fixed soon.


I appreciate al of yall help and i thank all of yall for the advice

Intercom to the fax extension proves nothing. As TTech recommended put the fax line on a CO port and ring it directly to the station port. See if that works.