Comtech EF Data CDM-600/600L - Manual (Page 271)

J–1
Appendix J. KT/11202-1 STEP
ATTENUATOR KIT (CDM-600L)
J.1 Introduction
The External 20 dB Step Attenuator Kit, CEFD P/N KT/11202-1, provides the CDM-600L modem
with the capability of extending the programmable output power range down to -60 dBm (-65 dBm
uncalibrated) from the standard -40 dBm (-45 dBm uncalibrated).
The following sections identify installation instructions, relevant front panel operations and remote
control commands for the KT/11202-1 External 20 dB Step Attenuator Kit for the CDM-600L
Open Network Satellite Modem.
J.2 Kit Installation
When the kit is installed, the CDM-600L (Firmware Ver 1.2.2 or higher) provides two set-up modes
for programming output power:
• The normal manual power mode allows the standard 0 dBm to -40 dBm (-45 dBm
uncalibrated) output power programming. In this mode, the external step attenuator is set
to minimum attenuation.
• The additional low power mode allows the output power programming from -20 dBm to
-60 dBm (-65 dBm uncalibrated). In this mode, the external 20 dB attenuator is switched in.
The external 20dB step attenuator on/off control is achieved by multiplexing a 5 VDC relay
activation signal onto the center conductor of the transmit output connector. The External
Attenuator design will not tolerate BUC power supply voltages, and will not pass 10MHz BUC
frequency reference or BUC FSK control signals. Hence, the External Attenuator kit is NOT
applicable in applications where the modem must supply BUC power supply, 10MHz frequency
reference, or FSK control.
The components included in the KT/11202-1 External 20 dB Step Attenuator Kit are shown in
Figure J-1.