modem: tone/pulse setting acts weird...

[VJ]

Hello,

My brother has a strange problem with the internal modem of a Compaq laptop. The modem is connected to a PABX (his own home-phone central). This PABX allows both the connection of pulse and tone-devices. We can verify this with the phones that are connected (they have a swith to set the to pulse/tone). And both work.

Now back to the laptop: setting the modem to dial in pulse works perfectly. However, when setting it to tone, it does not manage to get an outside line (needs to dial 0 first). You hear the internal dialtone, then the 0 being dialed, but the internal tone persists (in pulse, this then switches to the "normal" dialtone).

I have tested this with the AT-commands
ATDT0 -> no outside line
ATDP0 -> outside line

What could be causing this ? He is using Windows XP. It seems as if the PABX does not recognize the 0.


Jörg

[Fat Tone]

have you tried changing the duration of the tone? Maybe it is too short for the switch to detect properly?

T.

[VJ]

That's what I also thought, but I can't seem to find the setting in XP (I hate that OS ) to change the duration of the tone.

Jörg

[Fat Tone]

is it not an s register? I think you can make the modem give you the list, but its been a long long time since I could remember those commands. Good luck.

[VJ]

Oh, hadn't thought of that (I only knew the basic AT-commands by heart). Here's what I found on the web:

http://www.lothlorien.net/collections/computer/modem.html

-
S11
DTMF Tone Duration

Range: 50-255 milliseconds
Default: 95 milliseconds
-

So that is the one !
Thanks!!
(I don't know when I'll get to try it though)


Jörg

[Sasq]

Yeah I was thinking about that, usually for an outside line the dtmf tone needs to be a bit longer.
there is also a setting somewhere to make it use pulse for the first digit and and dtmf the rest, but its been so long I couldn't tell you what it is.

[VJ]

Nice thought, I think (according to some references I have found), it can be done with:
ATDP0T (followed by the number)
However, how can you set windows to dial like this for e.g. a dialup connection ?

Jörg

[Sasq]

i don't even have a modem to plug in, but there should be a setting somewhere in the modem properties to allow you to choose the dial string (or even a checkbox for the '0' outside line thing)

Dan

[VJ]

Yes, but it dials all the digits in the same manner (all pulse, or all dtmf)...

Jörg

[Fat Tone]

here's how to add the init string:

http://zero.colorado.edu/modems/win2k/init.html

HTH

T.

[VJ]

Thanks !
(I love this forum ! )

Jörg

[Fat Tone]

NP. Just let us know if that works.

T.

[VJ]

Will do!
(I just don't know yet when I'll get a chance to see my brother, could be a couple of weeks...)

Jörg

[VJ]

Well, I managed to try it, and altereing the length of the dial-tone doesn't change the PABX-behaviour. I have tried lengths up to 150 ms (the longest setting).

When setting the computer to dial in DTMF, the tones still aren't recognized by the PABX, however this DTMF-dialing works correctly for the phones connected to the same PABX (even when using the same socket). As stated before, once there is an outside line, the computer's DTMF dialing works perfectly (so ATDP0DTxxx will dial the number xxx correctly).

Any other things that might cause this odd behaviour ?

Thanks !


Jörg