Specifications

CI-1 and CI-8 Communications Interface
2-8
CI-8 RS-232C TO ACU CONNECTION
A null modem cable is used to connect the CI-8 to an ACU using RS-232C ports. Wires in the
cable are 22-gauge, stranded core. The maximum distance between an ACU and the CI-8 is 25
ft (8 m). Figure 2-8 shows the minimum wire connections required between the CI-8 and either
a 25-pin or 9-pin ACU host port.
The AC power to all RS-232C devices must have a common ground to prevent ground potential
differences. Such differences can cause loss of data.
Figure 2-8: CI-8 RS-232 Connection
CI-8 TO HOST COMPUTER CONNECTION
Connection between the CI-8 and a host computer is made through RS-232 ports. Cable type,
maximum length and wiring are identical to that described for the RS-232 ACU connection above.
(For a 25-pin host connection use the wiring on the left of Figure 2-8; for a 9-pin host, use the wiring
on the right.) All RS-232 devices including the host computer, must have a common ground to
avoid faults.