Changing from Voice Mode to Data Mode

[muhammadabdulsamad]

Dear All!

Have a nice day!

Now-a-days i am developing an application where .....

User wants to dial through Phone set to other telphone. He wants to talk to the person other side. He want to transfer files Using PC+Modem(on both sides) using the same telephone call without disconnecting phone. (He don't want to drop/disconnect call)
How can i connect two applications using VB+MSCOMM in this case? I know little AT,&,%,/ and Voice Commads of modem . But i am still fails to find some commands to connect to modems on pre-established telephone call! please help me

Thanks for your valuable time.......
Regards
Samad

 

[SteveGlover]

The following should work: (don't send the " characters)
Establish the voice call by sending "ATDTxxxxxxx;" where xxx is the phone number to dial.
The modem should immediately respond OK, and its now back in command mode with the voice call open.
To put the modem into data mode send it "ATDT" without a phone number. It should try to connect in data mode. The modem at the other end must also be put into data mode, otherwise the modem will time out and respond "NO CARRIER".

This works with my Hayes modem.