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 |