Dtu

Hi
I had a similar problem when going from an older laptop with a PCMCIA card modem to a newer laptop with built-in (software modem) doesn't handshake properly after answering. Only happens when connecting to the two older PABX's that I look after not the newer one. I can't speak for the programs that you use, I am using Procomm Plus.
Some of the Network guy's here have also experienced problems connecting to other things using newer laptops with built-in modems dialing in to older equipment.

NECTECH

If anyone has sorted this problem before, please let me know

Dtu

I actually had to go back to using an older PCMCIA card modem and not use the laptops in-built modem.

It is also a problem with some of the newer V.92 external modems the new protocol does not like handshaking with older modems.

I've had to resort to an older 14400 modem on my work desktop to connect to one of our PABX's.

pimonsak

I think this problem dose not from NEC 2400 SDS
please re check modem configulation about dial out, in case you use extension number to out-going you must use prefix 9,
however, recheck COMMAND trunk rout parameter only DTMF or PLUSE kind of dial

good luck

NECTECH

Yeah, I must see if I can get hold of an old PCMCIA modem.....

I tried stripping the V92 off the modem back to V34 and made no difference.......

ClassOfService

With the newer modems that are v.92 (most chipsets, with the exception of certain USR Winmodems) can disable v.92 and downgrade to v.40 or v.42: (All of these commands are utilized by the AT command set...) You'd have to ensure that your terminal program sends these initialization strings before it dials out)

V.44 Compression - V.44 and V.42 are enabled/disabled with the +DS44= command.
The V.250 spec includes up to 9 numeric values. The first two values control direction and compression negotiation:

+DS44=direction,compression-negotiation where
direction = 0, 1, 2 or 3:
0 = No V.44
1 = V.44 on Transmit Only
2 = V.44 on Receive Only
3 = V.44 in both or any direction

compression negotiation = 0 or 1:
0 = Do not disconnect if V.44 is not negotiated in specified direction
1 = Disconnect if V.44 is not negotiated in specified direction

The additional 7 values, which may not be supported in all client modems, specify capability, maximum codewords, stringsize, and history:

Capability: 0,1, or 2 where 0=Stream method; 1=Packet Method; 2=Multi-packet method
Maximum codewords (tx and rx) = 256 - 65536
Maximum stringsize (tx and rx) = 32 - 255
Maximum history (tx and rx) = 512 - 65536

To examine your modem's setting: AT+DS44?
To list valid values for your modem: AT+DS44=?

Some Lucent/Agere modems use +DCS (not a V.250 command) to control compression:
+DCS= command:
+DCS=#,# where # = 0 or 1. The first # is for V.42, the second for V.44; a value of 0 disables, 1 enables.
To disable V.44 but keep V.42: +DCS=1,0

You can also try to disable the v.92 quick connect feature by doing so:

Quick Connect - The command +PQC=# controls Quick Connect. The values are - 0 to enable Quick Connect (short phase 1 and phase 2 enabled); 1 - enable short phase 1 only; 2 - enable short phase 2 only; 3 - disable short phase 1 and phase 2.



** NOTE
US Robotics V.92 modems: Only the 5699B Winmodem, and the 5660A Softmodem support V.44. USR hardware-controller based models do not support V.44.

** ANOTHER ITEM

I've had better success if I keep the port rate on the COM port on the laptop or PC I'm using at 19200 vs higher baud rates.