Mn/Cdm570L.iom - Comtech EF Data CDM-570L Installation And Operation Manual

CDM-570L Satellite Modem with IP Module
IEC line input connector
The IEC line input connector contains the ON/OFF switch for the unit. It is also fitted
with two fuses, one each for line and neutral connections (or L1, L2, where appropriate).
These are contained within the body of the connector, behind a small plastic flap.
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For continued operator safety, always replace the fuses with the correct type and rating.
IMPORTANT
Rx and Tx IF connectors
The IF port connectors are both a 50Ω 'N' female type. The return loss on these ports is
greater than 19 dB (typically better than 21 dB), and if the user wishes to connect to a
75Ω system, an inexpensive 'N' to 'F' type adapter can be used. While there will be a
reduction in return loss when doing this, the effect in most systems will be imperceptible.
Data interface connector
The Data connector is a 25-pin 'D' type female (DB25-F). This connector conforms to
the EIA-530 pinout, which allows for connection of different electrical standards,
including EIA-422, V.35, and EIA-232. A shielded 25-pin 'D' type provides a very solid
solution to EMC problems, unlike the sometimes used V.35 Winchester connector.
It is the responsibility of the user to provide the appropriate cables to connect to
this EIA-530 connector.
IMPORTANT
External reference connector
This is BNC female connector. The signal supplied here by the user is used for phase-
locking the internal 10MHz reference oscillator, and can be 1, 2, 5, 10 or 20 MHz. The
impedance is matched for 50/75Ω, and requires a level in the range –6 to + 10 dBm.
Form C Traffic alarm connector
The Alarms connector is a 15-pin 'D' type male (DB15-M). This provides the user with
access to the Form-C relay contacts which indicate the fault status of the unit. These are
typically connected to an external fault monitoring system, often found in satellite earth
stations. In addition, the receive I and Q demodulator samples are provided on this
connector. Connecting these signals to an oscilloscope in X,Y mode will provide the
receive signal constellation diagram, which is a useful diagnostic aid. A pin is also
For 230 volt AC operation, use T2.5A, (slow-blow) 20mm fuses.
For 115 volt AC operation, use T5.0A, (slow-blow) 20mm fuses.
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MN/CDM570L.IOM