3COM CORPORATION
VARMODEM 1200
| 
 Modem Type  | 
 Data (synchronous/asynchronous)  | 
| 
 Maximum Data Rate  | 
 1200bps  | 
| 
 Data Bus  | 
 8-bit ISA  | 
| 
 Data Modulation Protocol  | 
 Bell 103A/212A ITU-T V.21, V.22  | 

| 
 CONNECTIONS  | |||
| 
 Purpose  | 
 Location  | 
 Purpose  | 
 Location  | 
| 
 Line out  | 
 CN1  | 
 Volume  | 
 R1  | 
| 
 Line in  | 
 CN2  | ||
| 
 MULTI-LINE INSTALLATION  | |
| Setting | 
 J1  | 
| » Single modem | 
 Off  | 
| Multi-line | 
 On  | 
| 
 TRANSMISSION FORMAT  | |
| Setting | 
 J2  | 
| » 10-bit | 
 Off  | 
| 11-bit | 
 On  | 
| 
 RESET  | |
| Setting | 
 J14  | 
| » Enabled | 
 Off  | 
| Disabled | 
 N/A  | 
| 
 FACTORY CONFIGURED SETTINGS  | |
| 
 Jumper  | 
 Setting  | 
| 
 J3  | 
 On  | 
| 
 BASE I/O ADDRESS SELECTION  | ||
| 
 Port  | 
 J10  | 
 J11  | 
| 
 COM1: (3F8h)  | 
 Pins 2 & 3 closed  | 
 Off  | 
| 
 COM2: (2F8h)  | 
 Pins 2 & 3 closed  | 
 On  | 
| 
 COM3: (3E8h)  | 
 Pins 1 & 2 closed  | 
 Off  | 
| 
 COM4: (2E8h)  | 
 Pins 1 & 2 closed  | 
 ON  | 
| 
 INTERRUPT SELECTION  | |
| 
 IRQ  | 
 J12  | 
| 
 3  | 
 Pins 2 & 3 closed  | 
| 
 4  | 
 Pins 1 & 2 closed  | 
| 
 AUTO ANSWER  | |
| Setting | 
 SW1/1  | 
| » Off | 
 Modem answers on first ring  | 
| On | 
 Modem does not answer on first ring  | 
| 
 CARRIER DETECT  | |
| Setting | 
 SW1/2  | 
| » Off | 
 CD normal  | 
| On | 
 CD forced high  | 
| 
 PBX MODE  | |
| Setting | 
 SW1/3  | 
| » Off | 
 Normal dial up line equalization  | 
| On | 
 PBX operation  | 
| 
 DTR SIGNAL  | |
| Setting | 
 SW1/4  | 
| » Off | 
 DTR normal  | 
| On | 
 DTR forced high  |