Switching modems from voice to data




First off thanks for a mighty magazine. I was wooed from a rival publication in '94, (at the Brisbane Computer Show if I remember aright) and I'm still with you! Your guide to connecting to another computer via the modem was spot on -- I tried it! But, here is a curly one for you: how do you get the modems to talk to each other when you have already established a voice connection and you then wish to send or receive a file or two without having to hang up and let the computer dial out again?
I have tried typing ATX 1D on the sending computer and ATA on the receiving one. But after a few weird sounds, nothing (the X1 command means ignore dial tone and busy signal; the D command means dial; the ATA command places them modem in answer mode).
Any advice from yourself or readers will be greatly appreciated by me and many others I expect. By the way, when connected via modem to a friend's computer and you want to type messages to each other, to see what you type on your screen, you have to set your comms program to allow local echo ON (doesn't apply when connected to a BBS etc). This will allow you to edit your message if you make a mistake before pressing enter to send. Finally, thanks to all who send in questions and thanks to you and your staff for ferreting out the answers. I ain't 'arf learned a lot... !
- Rod Dent


I know what you're thinking, Rod -- if a fax machine can take over from a voice call using the manual send feature, why can't a modem?
Let's assume that your modem and telephone handset are plugged into the same telephone line. If you establish a voice connection using a handset then it is possible to let the modems take over if you are careful.
Both callers enter Terminal mode in their communications packages. One caller issues ATD<Enter> and then after a few seconds the other caller issues ATA. Both callers must stay absolutely quiet during all of this, otherwise the connection will not succeed. Once the connection is made, both ends must place the handset down gently and quietly. (Thanks to Shane Lord/Technical Services/NetComm Customer Care Centre)
Although this method is possible, it is generally better to let your modem do the dialling thus keeping the line quiet for maximum connect speeds.
As you say, if you are running a basic communications package like Microsoft Terminal you can echo characters to your friends screen via the modem. I suggest however you get yourself a deal with an ISP (Internet Service Provider) and meet in real time on an IRC (Internet Relay Chat) server. You can directly chat with your friend and a few other people as well. The only trouble with this is that you're paying for a local call as well as connect time on your ISP!
Your "echo" method is basic but definitely cheaper. Maybe it's time to get multi-user DOOM configured for your modem!
- Ian Yates


Category: Hardware
Issue: Oct 1996
Pages: 176-177

These Web pages are produced by Australian PC World © 1997 IDG Communications