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Snm-1000 commands, Character set, Status lines and flow control – Comtech EF Data SNM-1000 User Manual

Page 94: Message structure

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SNM-1000 Node Control Modem

Revision 3

Operation

MN/SNM1000.IOM

3–52

3.7 SNM-1000

Commands

The commands described in this section are used to set SNM-1000 functional parameters
within a DAMA environment. Refer to Appendix A for commands used to communicate
with external modems attached to an SNM-1000.

3.7.1 Character

Set

The interface responds to ASCII characters in the range of 0x00 to 0x7F. The 8th bit
(most significant) is not generated on the transmit side and is ignored on the receive side.

3.7.2

Status Lines and Flow Control

The interface ignores all status inputs.

3.7.3 Message

Structure

A message is either a command or a response. Each message is made up of three
elements:

• Prefix
• Message body
• End character

3.7.3.1 Prefix

The prefix consists of the channel number in ASCII decimal, with a valid range of 0
through 30. Leading zeros are ignored. Prefix 0 is valid for an SNM-1000 Node Control
modem and prefixes 1 through 30 are valid for external traffic modems attached to the
SNM-1000 such as SDM-300s, SDM-6000s, etc.