CANOGA PERKINS 2270 Fiber Optic Modem - Manual (Page 17)

17
2270 Fiber Optic Modem
Repeat this procedure for the second modem using the center cover retaining screw on the right
side of the modem. After the modems are secure, you can mount the shelf into the equipment
rack.
NOTE: Depending on accessibility, it may be necessary to connect the fiber cables and
interface cables before mounting the 2202 shelf in the equipment rack.
NOTE: The modem must always be removed from the 2202 shelf, and its top cover re-
moved, to access any switches inside the case.
2.4 Fiber Cable and Connectors
The proposed fiber optic cable must provide adequate bandwidth and power loss characteristics
for the intended modem link. Furthermore, the terminated cable must match the connectors on
the modems: typically, ST.
The connectors on the fiber optic cable, when supplied by Canoga Perkins, are marked Tx and Rx,
and should be connected to matching connectors on the modem. That is, Tx to Tx, and Rx to Rx.
This will link the Rx of the local modem to the Tx of the remote modem, and the Tx of the local
modem to the Rx of the remote modem.
The connectors are clearly marked as to their function, either Transmit (Tx) or Receive (Rx), on the
rear panel of the 2270 standalone units, and on the rear of the 2201 Rack Chassis.
NOTE: Keep all connectors free of water, dust and dirt. Cover them and the cable ends
with plastic caps when they are not mated.
The 2270 can be used with most popular sizes of multimode and single mode optic cable, includ-
ing 8-10/125, 50/125 and 62.5/125. Do not mix multimode and single mode fiber optic cables.
NOTE: When using 85/125 or 100/140 micron fiber optic cable, an in-line attenuator may
need to be installed between the 2270 and the Receive (Rx) fiber optic cable for proper
modem operation on short links.
2.5 DC Power
A DC-powered version is available for use with a nominal +/-48 VDC source (
+/−
36 to
+/−
72VDC
at 0.5A). Units are supplied with a 5-foot, three-wire cable terminated with a three-pin Molex
connector (Part Number [P/N] 19-09-1036; female pins P/N 02-09-1119). The mating connector is
Molex P/N 19-09-2036 (with male pins P/N 02-09-2118).
Power input pin designations are:
Pin # Signal
1 (odd shape) +Vin (RED)
2 Chassis (EARTH)
Ground (WHITE)
3 -Vin (BLACK)
The DC/DC converters isolate input and output so that either polarity DC input can be used.
Normally, Pin 2 (Chassis Ground) is connected to one of the two voltage pins. Protection diodes
on the converter board prevent damage from input polarity reversal. Fuses are soldered in place to
protect the modem from excessive voltage inputs.