Iec Line Input Connector; Rx And Tx If Connectors; Data Interface Connector; External Reference Connector - Comtech EF Data CDM-570 Installation And Operation Manual

CDM-570/570L Satellite Modem with Optional IP Module
Physical Description
4.3.1

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
4.3.2

Rx and Tx IF Connectors

CDM-570L: 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.
CDM-570: The IF port connectors are both a BNC female type. The return loss on these
ports is greater than 17 dB (typically better than 19 dB) in BOTH 50Ω and 75Ω systems.
4.3.3

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
4.3.4

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.
For 230 volt AC operation, use T2.5A, (slow-blow) 20mm fuses.
For 115 volt AC operation, use T5.0A, (slow-blow) 20mm fuses.
4–3
Revision 3
MN/CDM570L.IOM