Comtech EF Data SNM-1010L - Manual (Page 163)

Chapter 6. THEORY OF
OPERATION
This chapter describes the theory of operation for the following printed circuit boards
(PCBs) contained in the SNM-1010L.
• DAC
• Monitor & Control (M&C) Board
• Terrestrial Data Interface
• Modulator
• Demodulator
6.1 Demand Assignment Controller (DAC)
The DAC implements DAMA control inbound/outbound signaling and DAMA remote
signaling/traffic applications within the modem. The DAC is capable of remotely
controlling in-circuit reconfiguration of the DAMA microcontroller code.
The DAC performs the following functions:
• Decodes a network control HDLC encoded data stream from the demodulator
• Encodes a burst signal using HDLC encoding
• Synchronizes transmit burst to control slot time
• Controls the data interface
• Controls the modem M&C board via a serial link
• Supports two EIA-232 user interface ports
6–1