IBM LPCI-COM-4SM, LPCI-COM-8SM, LPCI-COM232-4, LPCI-COM232-8

Parameter Conditions Min. Max.

Driver Output Voltage (unloaded) 4V 6V

-4V -6V

Driver Output Voltage (loaded) LD and LDGND 2V

jumpers in -2V

Driver Output Resistance 50Ω

Driver Output Short-Circuit Current +150 mA

Driver Output Rise Time 10% unit interval

Receiver Sensitivity +200 mV

Receiver Common Mode Voltage Range +7V

Receiver Input Resistance 4KΩ

Table A-2: RS422 Specification Summary

To prevent signal reflections in the cable and to improve noise rejection in both the RS422 and RS485

mode, the receiver end of the cable should be terminated with a resistance equal to the characteristic

impedance of the cable. (An exception to this is the case where the line is driven by an RS422 driver that

is never "tristated" or disconnected from the line. In this case, the driver provides a low internal

impedance that terminates the line at that end.)

Note

You do not have to add a terminator resistor to your cables when you use the card. Termination resistors

for the RX+ and RX- lines are provided on the card and are placed in the circuit when you install the Ch X

- LD jumpers. (See the Option Selection section of this manual.)

Manual LPCI-COM-8SM