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PSM-500/500L/500LT SCPC Satellite Modem
Description
1.2.9 Optional Interface Capability
The M500 modems are also capable of accepting optional interface cards to replace the standard
synchronous serial interfaces. The first of these cards is the Ethernet interface embodied in the
Datum Systems' Satellite Network Interface Processor, or "SnIP". The SnIP is more fully explained
in Appendix SNIP.
A second specialized interface card available is a High Speed Serial Interface or HSSI that is
commonly used for connection to some routers. The HSSI interface is more fully explained in
Appendix HSSI.
For users that require the option to select either SnIP or HSSI interfaces in addition to the standard
synchronous serial interfaces, both cards can be installed in a "stacked configuration.
Installed option interfaces are automatically recognized by the modem, making them a selectable
option on the front panel or remote control protocols.
1.2.10 Modem Circuit Implementation
Much of the functionality in this modem has been achieved by incorporation of extensive circuitry
into Digital Signal Processing parts and Field Programmable Gate Arrays (FPGA). Depending on
features and options installed there are between 1.2 and over 2 Million gates of logic encapsulated
in the FPGAs, a 10 fold increase over the last generation modem. The logic can be augmented and
changed as requirements change. The modems unique direct modulation and demodulation scheme
also completely eliminates all IF mixing and filtering circuitry.
PSM-500/500L/500LT - Rev. 0.91
Page 1-21
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