WLL technical problem

oscarBravo

Fishing desperately for ideas here:

I have two phone lines. One is the regular 'orrible carrier line, 24k on a good day, unreliable connections. The other is the nice shiny new consistent 45.2k WLL line. Guess which one I use for dialup? That's right.

The problem is this: when I dial up (to UTV Internet FWIW), it's a bit flakey for the first few seconds. The norm was for the Verifying User and Password dialog to sit there for ages, and eventually to timeout and abort the connection.

So, I set the connection to bring up a terminal window. The problem turns out to be that after the modem gives the CONNECT message, there's a delay of sometimes up to 15 seconds before the user and password prompts. After about 10 seconds, the automated process times out.

So, I plugged headphones into the modem (Askey external serial jobby) and listened hard: turns out the modem has to retrain, or re-handshake, or whatever, immediately after it decides it has negotiated the connection. I can tell this because the modem doesn't completely mute after it connects, but just gets really quiet, and you can still hear what's going on.

The meat of the problem is this: I'm pretty sure this is a problem with Eircom's configuration of the WLL kit. I had a problem with the line before, and they got an engineer from Airspan (the equipment suppliers) to have a look at it. I got talking to him, and he showed me some of the Eircom configuration data which he said was done wrongly.

What do I do? You can just imagine me ringing 1901 and explaining all this to the nice lady in Repairs. The real problem is that technically, the line works, but it's a nuisance having to open the terminal window every time, so in a sense I don't have a line fault. And that's entirely outside the fact that Eircom don't recon they are under any obligation to provide data capability on a dialup line anyway.

Sorry about the length of the message, but I'm hoping somebody has a useful idea how to get this sorted.

Snowbat

Check your modem manual or look up online details of your modem's registers (these are model-specific). I once cured a random disconnect problem by increasing the carrier loss disconnect time in the register. I also reduced the DTMF tone duration for rapid dialling. Remember to save the new profile.

oscarBravo

This is not a random disconnect problem. The landline doesn't exhibit this problem at connect time, just the WLL line. I want to keep using the WLL line, because it's twice as fast and never disconnects, but it's behaving strangely just once, immediately after connecting.

Like I said, I'm pretty sure it's a misconfiguration of the equipment at the exchange end. The only variable is the line used: the same PC and modem dialling into the same provider, but when I use the WLL line I get this problem.

Still looking for ideas on how to get this through to Eircom.

Snowbat

Your modem starts retraining a few seconds after it connects on the WLL line (during user authentication). Carrier is lost during retraining - you'll see the CD (carrier detect) LED go out if you have an external modem. _IF_ your modem's Carrier Loss Disconnect Time is reached before the retraining is complete, your modem will hang up the line.

Try increasing your CLDT by 10 seconds and see if it helps.

oscarBravo

Thanks again Snowbat, but the problem is not the modem dropping the line during retraining. The problem is that the retrain process takes longer than DUN is prepared to wait. If DUN doesn't get a User: prompt within a second or so of the CONNECT signal, it starts stupidly sending CRs once every couple of seconds, and hangs up after about 10. If I enable the terminal window, I sit and stare at a blank terminal for about 15 seconds, then the User: prompt appears and I can continue manually.

In short, the problem is not trying to get the modem to cope with the retrain, it's trying to get DUN to cope with it, or preferably make the problem go away altogether.