Mocomtech CDM-570 - Manual (Page 11)

CDM570/570L Satellite Modem MN/CDM570L.AA4
Incorporate NMCS Protocol
Page 7 of 54 MN/CDM570L.AA4
3.3.1 Start Of Packet
Controller to Target: This is the character ‘<’ (ASCII code 60)
Target to Controller: This is the character ‘>’ (ASCII code 62)
Because this is used to provide a reliable indication of the start of packet, these two characters
may not appear anywhere else within the body of the message. For multi line text message, each
line should end with a new line character ‘\n’. The carriage return & new line [\r\n] combination
should present only at the end of the message.
3.3.2 Address
Up to 9999 devices can be uniquely addressed. Even though the any number of devices can be
addressed, but they all should be associated with single IP Address.
• For a CDM570, address of ‘1’ is being used to address both modulator and
demodulator.
• For CDD564, each demodulator is identified by unique address from 1 to 4
respectively for all the four demodulators.
The address is not significant for commands targeted system wide. But, it does has significance
when associated with demod specific commands like Frequency, data rate etc.
IMPORTANT
The controller sends a packet with the address of a
target - the destination of the packet. When the target
responds, the address used is the same address, to
indicate to the controller the source of the packet. The
controller does not have its own address.
3.3.3 Instruction Code
This is a three-character alphabetic sequence that identifies the subject of the message. Wherever
possible, the instruction codes have been chosen to have some significance.
For example, TFQ stands for Transmit Frequency, RMD is for Receive Modulation type, etc.
This aids in the readability of the message, should it be displayed in its raw ASCII form. Only
upper case alphabetic characters may be used (A-Z, ASCII codes 65 - 90).