Owner`s manual

15
Chapter 2 - Installation
If you are connecting your phone lines (-21 series rack) to
the 50-pin connector on the backplane of the rack, plug
the appropriate phone cable into the appropriate 50-pin
connector (RJ21X). RJ21X connectors are TN circuits.
Note: Three 50-pin connectors are mounted on the back
of the -21 series rack backplane. The left 50-pin
connector (labeled Dial-Up/2-Wire Leased Line) is used to
connect all the modems in the -21 series rack to dial-up
phone lines. When 4-wire leased lines are being
connected, the two right 50-pin connectors (labeled 2-wire
Lease Line/4-wire Transmit Pair on the right and 4-wire
Receive Pair in the center) are used to connect the rack to
leased lines. When connecting to 2-wire leased lines, you
must first determine if your modem has dial back-up
capability. If it does, then use the right connector. If it
does not, then use the left (2-wire Lease Line) connector.
13. If an AC power source is being used, plug the AC power
cord supplied with the rack into the power cord connector
on the back of the rack and to a live AC outlet.
If a DC power source is being used, connect the negative
lead from the DC supply to the left terminal on the terminal
block on the back of the rack and the positive lead from
the DC supply to the right terminal on the rack.