No Ring on Modem

[Jason777]

Hello all, I was at a clients office today, they have a Win2k Server with a dial in external modem. They have not been able to connect for a week or so. I called the phone # on my cell phone. Ring but no answer. Ok possibly a bad modem. I carry a US Robotics modem in my toolbag. I set the dip switches to answer after 1 ring. I called again... Nothing. I then opened up a terminal emulator on my laptop, plugged in the line, and dialed the number on my cellphone again. Usually when the modem detects a ring, it returns with RING. It did not. To confirm my thoery I plugged my laptop into their fax line and called that #. It returned with a RING on the screen. There is a dial tone on the line in question, and if I ATA from the terminal it will pick up. Around the same time this happend, they had static on their PBX system and had the phone company come in to fix it. The telco tech metioned something about the POTS line in question, but nobody remembers what he said about it.
I thinkg there is something wrong with the phone line, possibly a bad ground.

Can anyone offer me a second opinion?

 

[franklin97355]

Sounds like the number you are dialing does not go to the jack your modem is plugged into. If it's on a pbx system get with the guys that maintain that and make sure the number is correct.

 

[edfair]

Diagnosis would probably require a phone plugged into the line to see if ring voltage is coming in. Alternative is AC 150 v setting on VOM thru a capacitor to see what ring voltage is comeing in.
The one major problem I had like this ended up being the carbon discharge links in the central office. Mine would ring once then quit. Drove my customers wild when they couldn't get my answering machine. Ended up with the VOM across the line to show a telco rep the problem. He replaced the local links and sent in a trouble report to CO and 3 days later the problem disappeared.

Ringing voltage is provided by circuitry controlled by line current so it is possible for a partially shorted line to affect it.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[Jason777]

Thanks for the quick replies. I am certain that the jack is correct because you can pick up the line using ATA. The modem just does not know that the line is ringing to pick it up by itself. Also, one of the secretaries remembered the telco tech saying that the wiring didn't look right to him. I didn't have an analog phone with me to test to see if it would ring. All in all its a very perplexing situation.

 

[ceh4702]

I have seen lines that do not work because they are not disconnecting properly. After they disconnect they just act like they are dead as far as the modem is concerned. I had a house modem do that and it had a service box and I disconneced the connector (phone plug) and plugged it back in a couple of times. I thing sometimes after a while the metal corrodes or gets dust buildup or something. Anyway it worked fine after that.

If you do not like my post feel free to point out your opinion or my errors.

 

[franklin97355]

Try calling the number and shorting the tip and ring at the jack. Or tell the modem to pick up the line while it is ringing. This should cause the line to quit ringing in the calling phone.

 

[BillPSU]

Your modem may have the auto answer turned off and the software on the server may be doing it at initiallization. Another problem may be the PBX. Lines can be configured at the PBX to do just about anything these days and it may not be allowing calls to go to that number only outgoing calls for security reasons.