3COM CORPORATION
VARMODEM 2400
| 
 Modem Type  | 
 Data (synchronous/asynchronous)  | 
| 
 Maximum Data Rate  | 
 2400bps  | 
| 
 Data Bus  | 
 8-bit ISA  | 
| 
 Data Modulation Protocol  | 
 Bell 103A/212A ITU-T V.21, V.22, V.22bis, V.23  | 

| 
 CONNECTIONS  | |||
| 
 Purpose  | 
 Location  | 
 Purpose  | 
 Location  | 
| 
 Line out  | 
 CN1  | 
 Volume  | 
 SW2  | 
| 
 Line in  | 
 CN2  | ||
| 
 BASE I/O ADDRESS SELECTION  | ||
| Port | 
 J3  | 
 J4  | 
| » COM1: (3F8h) | 
 Off  | 
 Pins 2 & 3 closed  | 
| COM2: (2F8h) | 
 On  | 
 Pins 2 & 3 closed  | 
| COM3: (3E8h) | 
 Off  | 
 Pins 1 & 2 closed  | 
| COM4: (2E8h) | 
 On  | 
 Pins 1 & 2 closed  | 
| 
 INTERRUPT SELECTION  | |
| IRQ | 
 J5  | 
| » 4 | 
 Pins 1 & 2 closed  | 
| 3 | 
 Pins 2 & 3 closed  | 
| 
 DTR SIGNAL  | |
| Setting | 
 SW1/1  | 
| » On | 
 DTR forced high  | 
| Off | 
 DTR normal  | 
| 
 RESULT CODES  | |
| Setting | 
 SW1/2  | 
| » Off | 
 Verbal result codes enabled  | 
| On | 
 Numeric result codes enabled  | 
| 
 RESULT CODES DISPLAY  | |
| Setting | 
 SW1/3  | 
| Off | 
 Display disabled  | 
| » On | 
 Display enabled  | 
| 
 ECHO COMMANDS DISPLAY  | |
| Setting | 
 SW1/4  | 
| » Off | 
 Local echo enabled  | 
| On | 
 Local echo disabled  | 
| 
 AUTO ANSWER  | |
| Setting | 
 SW1/5  | 
| » On | 
 Modem does not answer on first ring  | 
| Off | 
 Modem answers on first ring  | 
| 
 CARRIER DETECT  | |
| Setting | 
 SW1/6  | 
| » Off | 
 CD normal  | 
| On | 
 CD forced high  | 
| 
 MULTI-LINE INSTALLATION  | |
| Setting | 
 SW1/7  | 
| » Off | 
 Single phone connected  | 
| On | 
 Multiple phones connected  | 
| 
 AT COMMAND SET  | |
| Setting | 
 SW1/8  | 
| » On | 
 AT command set recognized  | 
| Off | 
 AT command set disabled  | 
| 
 ESCAPE CODE  | |
| Setting | 
 SW1/9  | 
| » On | 
 Go to command mode and display OK result code when escape character is received  | 
| Off | 
 Disconnect, go to command mode and display NO CARRIER when escape character is received  | 
| 
 VOLUME CONTROL  | |
| Setting | 
 SW1/10  | 
| » Off | 
 High volume  | 
| On | 
 Low volume  | 
Proprietary AT Command Set
See document V1254 for a full command summary.