Independent Tx And Rx Function; Verification; Updating Modem Firmware - Comtech EF Data SLM-5650B Installation And Operation Manual

1.3.3.4

Independent Tx and Rx Function

The Tx (modulator) and Rx (demodulator) sides of the modem are functionally independent and
separately controllable. The baseband Tx and Rx sides of a communications channel passing
through the modem are independently configurable, including the ability to select different
parameters (to include data rate, modulation, and coding) in support of asymmetrical operation.
Data interfaces and IF interfaces are not independent.
Example:
If the TIA/EIA-530 interface is selected, DO NOT USE TIA/EIA-530 to transmit and a
HSSI interface to receive. The same principle applies to the IF interfaces: If 70/140 is
selected, DO NOT USE 70/140 to transmit and the L-Band interface to receive.
1.3.3.5

Verification

The SLM-5650B includes test modes and loopbacks for rapid verification of the correct
functioning of the modem. Of particular note is the IF loopback, which permits the user to perform
a quick diagnostic test without having to disturb external cabling. During the loopback, the receive
frequency is temporarily changed to match that of the Tx side, and an internal Radio Frequency
(RF) switch connects the modulator output to the demodulator input. When normal operation is
again selected, all of the previous values are restored.
1.3.3.6

Updating Modem Firmware

Chapter 4. UPDATING FIRMWARE
The SLM-5650B stores its firmware in flash memory, which allows the modem to upload firmware
downloads from an external PC once Ethernet connectivity has been established. Firmware
updates for the Base Modem and NP Interface Module may be obtained free from Comtech EF
Data via the CEFD Web site or via e-mail from Comtech EF Data Customer Support during
normal business hours.
TRANSEC Module firmware updates must be requested directly from
Comtech EF Data Customer Support.
Introduction 1–10
SLM-5650B Satellite Modem
Revision 2
MN-SLM-5650B