| Features |
| 4 RS-232 ports |
| ISA bus |
| Supports ADDC (Automatic Data Direction
Control) intelligence |
| Available with optical
isolation and surge protection as options |
| RS-485 data control: auto or by RTS |
| Built-in termination
resistors |
| CI-134I |
4 port RS-422/485 board with optical isolation |
| CI-134IS |
4 port RS-422/485 board with optical isolation and
surge protection |