Notes on modems and their configuration

The modem you use with your system MUST be a smart modem, of the type that sends the text 'RING' to the computer when someone dials in, the text 'CONNECT .....' when a connection is established, and the text 'OK' when a command is successfully executed in the modem. If you don't have this kind of modem then you won't be able to run the system! Whether or not the modem is eaxctly Hayes compatible or not doesn't matter too much, as you get to configure everything we are ever going to send to the modem in the CFGBBS program.

There are four different strings that are sent to the modem; the first one is the difficult one, and we will go back to it. The second is the command that tells the modem to 'answer' the phone and try to establish a connection with a user at the other end. The default string for this, 'ATA' is almost universal and should not give you any trouble.

The third and fourth strings are to tell the modem to take the phone off the hook, and put it back on again (the difference between the 'offhook' string and the 'answer' string is that the offhook string does just that and nothing else, while the answer string tells the modem that there is probably somebody out there and that we want to get a carrier signal going). Here again, the necessary commands are almost universal, and you can almost certainly leave the default strings as they are. These two commands are used to make sure that your callers get a busy signal if they ring while you are using the system locally or have the system down for 'repairs'. (NOTE if you are just putting the system up to test it, then you will want to exit from the system using the F3 key, not the F2 key, otherwise you will block your telephone line).

So: back to the first string. To find out what is going on here, we'll analyze the string that is used here on a Unimod 4161 modem, which is fairly typical as far as smart modems are concerned. The string used is

AT&FS0=0&C1&D2H0E0&G0+C0+M2

Breaking this down into pieces we get the following 'subcommands':

AT starts all Hayes commands

&F get factory settings (some BBS systems recommend that you set up your modem by storing the configuration into the modems internal memory : personally I like to have this where I can see it, in the BBS configuration)

S0=0 DON'T answer the phone automatically (the system will tell the modem when to answer the phone, with the ATA command)

&C1 Give true carrier detect signal to the computer. This is extremely important, as it will tell us if the user has disconnected.

&D2 Tell modem to monitor DTR and reset everything if it disappears. Also very important, it allows us to get into contact with the modem at any given time.

H0 Start off with the phone 'onhook' (i.e. users can dial in)

E0 Don't send commands back to the modem as they are sent from the computer.

&G0 No guard tones (may help some users get connected)

+C0 +M2 Specific to UniMod; what they are doing is to tell the modem (a) that we don't want the modem to do any speed conversion (the BBS will always run at the same speed as the user actually is using) (b) that we DO want the modem to detect the speed of the incoming call, and to switch to that speed (after telling us what the speed is with the CONNECT string).

That last piece is probably the one that gives most trouble; these commands seem to be different on just about every modem. Just remember when looking at your modem manual, that what we want the modem to do is to send us the CONNECT xxxx command at the same speed we used to set up the modem (usually 2400 baud), and then switch to that speed whatever it is.

Configuring MBBS 'under' a front door

Sometimes you won't want MBBS to handle incoming calls itself, either because you are using a front door program to pick up incoming calls that are not for the BBS or because you are sharing the line with a fax or similar equipment.

To configure a system like this, configure the system just as though were configuring for a modem but answer yes to the questions

Login directly (skipping menu) Direct connect (no modem) Use carrier signal for login

If you have set your modem up to use fixed speed then you will be able to configure the correct speed in CFGBBS, but if you are using the speed that the user logs in with to talk to the modem then you'll have to tell MBBS what speed it should be talking to the modem with - do this with the /B command line option (you have to find some way of getting hold of the speed from your front door program to do this of course). Note that on just about any modern modem then running at fixed speed is the best way of doing business, though!

If your front door program is able to supply you with information about what the actual line rate is then you can also supply this information in the command line using the /BU parameter. The /MNP parameter may also be used if the connection is using 'reliable' mode. Neither of these are essential but they will ensure that the 'whoson' display is correct and that calculations of file transfer times are done correctly. For example:

BBS config /BU 14400 /MNP

Sharing a fax

Often the above will also deal with sharing a fax - you just use a 'front door' that either starts your fax program or starts the BBS, depending on the connect type. If you wish to try another way of doing this, there is another function built into the system; if the connect string contains the word FAX, and if there is a file called FAXn.BAT (n=node number) then the BBS will run this BAT file. You can then use this to start your fax reception program.

In the same way if the connect string contains VOICE and there is a file VOICEn.BAT in the BBS directory then that BAT file will be run; use this capability to start your voice mail reception program if you have one.