sundance-communications.com/forum Forums General General Telephone & Systems Information Modem Line Test?

Hi,

I can't get a modem line to work. I have 12 remote locations that I use dial-up modem lines as backups for network router administration, and I haven't been able to get one of them working since the lines were first installed.

The phone company says everything is fine and in fact I can make and recieves calls at the demarc adn all the way up to the modem. The modem is only 4ft away from the demarc. I've swapped / tryed numerous modems at both ends. They all get hung in the hand shake phase.

Is there a specific test or terminology that I can bring up to the phone company for this line?

Thanks

Is your carrier providing you with POTS lines from a channel bank via a T-1 or a frac-T-1?? Compression of the lines may be a problem. Tell your provider. "Slips" also may be a problem for modems---while it doesn't seem to have an effect on voice traffic.

We are experiencing the same problem---we have talked to our provider for a month---but so far, we can't get a good handshake from the far end when we try to modem into our customers systems. Before we changed to the Digital circuit---we had POTS lines--everything was just fine.
Good Luck.

If the carrier has this connected to a slc or pair gain system. Timing errors or slips will also cause transmission issue

Most external modems today need to be setup prior to them working, usually they don't work right out of the box. You need to setup the modem for auto answer and the correct communications settings.
Have you be able to call out on the modem line to a known good working modem setup at a different location?
I'll bet that it's not the telephone lines in all 12 locations. Maybe the cable from the router to the modem or the modem setup.
What speed are to trying to connect at?

Sorry, I wasn't clear on my first post. Out of my 12 remote sites only one has this modem problem.

All this facility has is 6 POTS lines and the data T1. Five lines go to the Partner ACS phone sys., and the 6th is my modem line.

I am familiar with USRobotics modem configs I set up my other sites fine.

I'll try the rest of your suggestions.


Thanks

I'm not sure, but I think all the remote access test lines to test modems have long been abandon.

Added:: I put modem test line in google and all kinds of test sites come up, don't know if any of them would do you any good or not.

Sounds to me like you may have a noise issue. Does a fax work?

You could also have the phone company run and give you the results of a 5 point test.

Ahh, only one line has the problem. I agree with JWR and Anthony. SLCs and other pair gain equipment don't always play nice with data. It's not random like voice.

Have you temporarily tried the modem on any of the other 5 lines?

-Hal

This is a stretch but have you tried reversing tip and ring on the line?

not a stretch at all , a real possibility worth looking at

also take a look at loop current

I'm with skip555! High loop current, reversed pairs, even something else on the line , like the KSU, Credit card machine, G-- D-- alarm system(!), and then all the stuff that is a nightmare to find, like longitudinal imbalance, even an old , forgotten build out coil! Even a dangling half-tap. You know, a pair that goes out into the building and has nothing connected to it!
SO, check loop current, turn over pair and while you are at the MDF, look for other connections to the line and disconnect, temporarily or permanently. After all that, then start on the nightmare stuff! Good luck, and please let us know what you find! We all learn from these posts! John C.