The ASM Modem Selector is a device for the VSAT terminal to work with up to three satellite modems operating in the L-band frequency range (950 MHz to 2150 MHz).

The device is available in two versions:

• A – with a highly stable 10 MHz reference generator,
• B – without 10 MHz reference generator.

The VSAT terminal and modems are connected to the N-type connectors located in the rear of the selector housing. The version with the 10 MHz reference generator is additionally equipped with a power supply socket (230 V 50/60 Hz). The version without the reference generator is a passive device that does not require power supply.

The connectors are grouped into the sections:

• Tx/Rx – sockets for connecting the VSAT terminal
• Tx – Tx signal output to BUC and optionally 10 MHz reference signal,

Rx – RX signal input from LNB;

• MODEM [Tx] – sockets for connecting the TX outputs of modems 1-3;
• MODEM [Rx] – sockets for connecting the RX inputs of modems 1-3.

Each of the MODEM [Tx] inputs transfers the 10 MHz signal to the Tx output. Therefore, special attention should be paid to the configuration of satellite modems in this regard.

The test sockets (type N) for monitoring TX and RX signals are located on the front panel of the ASM.