C H A P T E R 4 F E A T U R E S
V100 Versatile Multiplexer Technical Manual Version 2.2
Page 167 of 231
Inmarsat networks) and so the Connection Timeout may be adjusted to ensure the V100 does not give up
too soon.
One final point to note is the clocking regime used with the switched system. Inmarsat terminals
commonly maintain a 64Kbps clock at all times irrespective of the connection state; in this case the
conventional scheme is used where the RX Clock is driven on to the GRX bus. With DAMA modems, since
the carrier is not permanently present, the mux must provide a TX clock to the modem at the intended
rate. This must also be used as the reference for the voice card, which generates call progress tones
during the connection sequence. A standard configuration is shown below:
4.12.2
SCADA Mode
The aggregate port should be configured with the word “SCADA” entered in the destination field. This
causes the port to adopt the SCADA packetised frame structure which supports the connection protocol of
the RF terminal to which it is connected: