1200 BPS Internal Modem (250-1013F) Features Faxback No. #4491 There are a few differences with this modem than the previous modems (25-1013 through 25-1013E). Three of the main differences are listed below: 1. With all of the previous modems, you could issue the command ATF0 or ATF1 to change it to half-duplex or full-duplex respectively. With the 25-1013F, this is not an option. The communications software that you are using must have this option available. 2. There is no jumper setting to define the modem as COM1 or COM2. There is a switch on the back of your modem that will set your modem as COM1 or COM2. 3. There is a Hayes command that will change the modem to work with either CCITT V.22 or BELL 212A lines. These commands were not available with all of the previous modems. ATB0 Selects CCITT V.22 ATB1 Selects Bell 212A (default) (abo-07/28/93)