Comtech EF Data SNM-1000 - Manual (Page 121)

SNM-1000 Node Control Modem Revision 3
Theory of Operation MN/SNM1000.IOM
4–3
4.1.1 Specifications
Refer to the following listing for specifications.
Physical Size 5.3 x 7 inches (13.46 x 17.78 cm)
The DAC board fits into the SNM-1000 1RU chassis.
Power Requirements +5 VDC
Operating Temperature 0 to +50
° C (32 to 122° F)
4.1.2 Theory of Operation
To ensure a high level of integration, the DAC uses the Intel 80386EX embedded
microcontroller. This 16/32 bit microcontroller performs DAMA controller functions
(and other functions) under control of a real time, multi-tasking operating system.
The DAC uses non-volatile configuration memory with unlimited read/write access to
satisfy memory reconfiguration requirements. Flash ROM is used for program storage.
NVRAM storage maintains the configuration parameters during power-down conditions.
HDLC synchronous serial ports are implemented with a Z85230 serial communications
controller device. This device supports the SNM-1000 control channel satellite channel
interface and the HDLC external serial port.
The 80386EX DMA channels are used for the satellite channel interface receive
functions. Additional asynchronous ports are implemented with 16C450/16C550
compatible UART devices, to provide monitor and control of modems under SNM-1000
control, via either the SNM-1000 microcontroller or a PC.
4.1.2.1 User Port
The User port serial interface is a 9-pin mini-DIN female connector (DCE) on the rear
panel of the SNM-1000. The interface operates at 19.2 kbit/s, 8 data bits, no parity, 1 stop
bit. The interface levels are EIA-232. The interface allows the user to configure the
SNM-1000 and to request the establishment and termination of data circuits.
Note: Refer to the following sections for a description of the software communications
parameters and detailed message format information.
Paragraph
No.
Nomenclature Description
3.5 User Port Operation Functional parameters for DAMA
enviroment.
Appendix A Remote Control Operation External traffic modem
communications.