Installation of the Digi C/X system consists of installing and configuring the host
adapter in your computer, connecting the C/CON concentrator(s) and installing
the device driver software. This manual covers the C/CON concentrator installa-
tion--installation of the host adapter and device driver software are described in
The C/X host adapter has two identical EIA-422 synchronous serial interface
ports to which a number of concentrators may be connected. Current versions of
Digi's device driver software support up to eight concentrators per host adapter,
which may be distributed in any combination between the two EIA-422 ports.
Multiple concentrators are connected to a single EIA-422 line in daisy chain
fashion--that is, the first concentrator is connected directly to one of the host
adapter's EIA-422 lines, the second concentrator is connected to the first, and so
C/CON concentrators can be connected to a C/X or EPC/X host adapter, and to
each other, in a variety of ways, including twisted pair cable, fiber optic cable,
synchronous modems, and combinations of these methods.
For local applications, where the work groups will not be located more than 300
meters (1000 feet) from the host computer, C/CON concentrators can be
connected to a host adapter via four or eight-conductor twisted pair cable. With
the eight-conductor cable, data is transferred between concentrators and the host
adapter at rates of up to 1.2 megabaud. With four-wire cable, the maximum
synchronous data rate is 460K baud. In most cases, when the concentrators are
used to connect terminals and printers, the reduced synchronous data rate on a
four-wire cable will not affect the performance of the system. For moderate to
heavy loads, however, the eight-wire connection is recommended.
When concentrators must be located more than 1000 feet from the host adapter,
a fiber optic link option, the Digi C/X-FL option, is available. With the C/X-FL
option, concentrators may be located up to 2000 meters (1.2 miles) from the host
adapter or other concentrators. Note that the C/X-FL supports only the 1.2
megabaud rate, and is therefore not recommended for use with remote
concentrators connected to the host adapter via synchronous modems.
Still greater distances can be achieved by using high-speed synchronous modems
between the host adapter and concentrators. By using modems, a remote
concentrator can be located anywhere in the world where there is phone service.