1. Home
  2. Telecom Technical
  3. no carrier problem

no carrier problem

Hi all,

I am using IBM T40 laptop with modem Agere systems Ac'97. I am using a device as a remote modem to dial in an try to stablish a connenction at 1200, 8-N-1, no protocal at all. I answer the call, but some how can't detect carrire. but I use this device to dail an old host, they can go throught. My init string is "AT&FE0B0N0Q0W1X6&Q6S7=150S0=2\\r". I

traced the phone line, if the deviceconnect to old host the trace is:

DCE [ R O R ] [ R N G ]

DTE 80 B2 SP D2 BS AK " A

82 80 SP VT A8

DCE [A T C ] [ A T B ] [ C D F E ] EQ

but if connect to my laptop the trace is:

DCE [ R O R ] [ R N G ] [ A T C ] [ A T B ] [ C D F E ] DTE

the remote modem does not send carrier at all. is there any configuration at answer modem to effect orginal modem's carrier?

any answer or help would be appericatiaed.

Reply to
jim
Loading thread data ...

You might have better luck trying a note in comp.dcom.modems newsgroup but here goes. If possible give them the modem brand/models of both modems and they should be able to get you working.

Yes, it is possible for some brands/models of modems to be set so that they do not send a carrier until they first hear your modem send a validation password to it during the period of initial silence. Only the person who set up the answering modem would know the password as there usually was not a "default" password built into them. Some modems can even be set to answer the line, hang up and then call back to the "calling" modem depending on a password and callback string the originating modem sends to it. I have even run into a situation that used the call back modem method and it would only call back to telephone numbers that were preconfigured into the modem.

Try calling the remote modem using your telephone and see if the modem actually sends a carrier signal for a short time after it answers. If it does then the problem is most likely with the calling modem. Modern modems usually are set to try to connect at the highest speed and then start trying to connect at other slower speeds. The old 1200 baud modems tend to not wait around for the newer models to get down to the 1200 baud range and time out the call. You would need to try a dial string that first locks your calling modem at 1200 baud on the Telco side and then make the call. With luck it will then be able to talk with the older/slower modem.

Reply to
GlowingBlueMist

Thanks a lot for response. I also post my question to comp.dcom.modems. In fact, I use another laptop(hyperterminal is set up as 1200 8-N-1, no protocol, no data compress) dial my IBM laptop, connection was set up at 1200, 8-N-1. I also can dial from my IBM laptop to dial old host to stablish connection. I am sure their no password at all. My laptop send carrier out for sure, I can see it on scope and i can hear the modem noise. I am going to make the device modem as an answer to see what happen.

Thanks aga> jim wrote:

Reply to
jim

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.