Modem to modem

Q: I would like to connect modem to modem with someone and transfer a file? Is this possible?
A: It is.

This is a common question on the Melb PC BBS, so I wasn't too surprised when the editor of PC Update asked me to turn my answer into an article. I've assumed that you want to send a file to your friend. The procedure works in reverse, but the steps and references to you (sender) and your friend (recipient) must be reversed. The instructions are generalised, because the specific commands you will use will depend on your comms program.

First you both have to prepare your communications (comms) programs and modems.

Test your settings

When you download a program from a BBS, after you select the file and select "Download" does the download begin without you also having to select "Download" in your comms program? If you answer "Yes" Auto-Zmodem-Download is turned on. If you answer "No" (and you must also select download in your comms program, then Auto-Zmodem-Download is not turned on).

Connecting

Now you can dial your friend and talk.

When you've finished talking, tell your friend (the recipient) to type ATX1D and press Enter, then to hang up the phone.

Then you type ATA and once the recipient's phone goes quiet (indicating the modem has picked up the line after the recipient has hung up) you also press Enter and hang up.

If your phone goes quiet after you press Enter then you might want to leave it off the hook. That way, if the modem-modem connection fails for some reason, then your phones will still be connected, and can try again for the same price!

The modems now "handshake" and connect, exactly as they would if one of them were a modem on the BBS.

Once you see CONNECT [XXXXX] (where a possible [XXXXX] represents the connect speed as well as any error correction/data compression protocols) you can type and the recipient will see your text on screen. You will not be able to see your own unless you have entered or enabled "Chat Mode". The manual for your comms program should explain how to do this.

The same goes for the recipient. (In Telemate chat mode is Alt+C and in Telix it is Alt+Y).

At this stage, if you don't want to "chat" (if you have done some "chatting" you should exit "Chat Mode" before you start uploading, this is usually done the same way as you entered it) all you need to do is to initiate a Zmodem upload (sending to your friend) and the transfer should progress as normal.

Uploading

To upload, you select Upload (usually with PageUp or Alt+S). Then you choose Zmodem as your transfer protocol. Then you select the file(s) you wish to send and choose "OK" to actually send them.

The actual upload procedure will depend on your comms program, so this is only an outline of the process.

Now, you've spent hours uploading and chatting and you want to go to bed...

Alt+H usually hangs up the phone. But, if you wish to "talk" (not "chat") to your friend before you hang up, then you (the instigator of the call) can pick up the phone and press Alt+H to tell the modem to hang up the phone (the modems will hang up by themselves, given time, after you pick up the phone). Once the modem at the other end has hung up your friend can pick up the phone, your phones will still be connected, and you can talk.

Note: remaining connected like this works on a local call, but I do not know if it works on an interstate/international call.

I hope that when you attempt a modem transfer with a friend, it goes smoothly. Adieu.

About the author
Michael Marquart is a Melb PC identity who is often found dispensing helpful advice in the echos of the group's BBS (that is when he's not stirring the inhabitants of General MSG area b/n members).

What is "Host" Mode?

Host mode is when your comms program runs a script (program) that enables you to run your machine as if it were a mini BBS.

It is easier than the process described in the main article, if you are going to be transferring files with any regularity, or if you want to do unattended file transfers. But it requires that you configure the script to recognise your PC's directory structure and file list, for normal use.

Tell your modem how and what to do

ATX1D tells the modem not to look for a dial tone, and to pretend to have dialled a number, thus to expect a modem to answer.

ATA instructs an answering modem to begin its answering sequence, as though the "S0" register
was set to "1" and the phone had just rung.

The S0 register

When ATS0=1 is used on a modem and the phone rings, it will pick up the line and listen for another modem;this is an alternative way to connect to a friend's modem.

You can set your modem to "AutoAnswer" by either including S0=1 in your modem's initialisation string in the comms program, and restarting it; or typing ATS0=1 at the terminal window (to which the comms program should return "OK"). After you have done this, the person with whom you wish to transfer files can dial your modem, which will automatically answer and connect.