XE924 Просмотр технического описания (PDF) - Xecom

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XE924

Base access point for multiple remote machines.

Xecom 

XE924 EMBEDDED MODEM

The modem embedded in the XE924 is Xecom’s XE2420

modem. The XE2420 includes FCC Part 68 Registration.

This registration can be applied to user equipment

without additional certification testing.

Modem Control

Industry standard AT Commands perform the control and

configuration of the embedded modem. To change

modem configuration or to initiate call, the remote node

on the 900 MHz network sends the desired AT commands

across the wireless link as data. The XE924

communications controller passes the AT commands to

the modem where they are executed. The modem

responses are returned across the wireless link to the

remote node.

Command Line Format

Command lines issued to the modem follow a strict

format. Each command begins with the prefix AT and

ends with a Carriage Return. The XE924 communications

controller sends all commands to the embedded modem

at 2400 BPS. The modem uses the AT command prefix to

automatically determine the parity of the incoming

characters.

Command Prefix - Each command, except the A/

command, begins with the AT prefix. The "A" and "T"

may be either both upper case or both lower case but

cannot be of different cases. The prefix identifies the

speed and parity of the commands sent to the modem by

the host. Speed is determined by measuring the width of

the incoming bits. Parity is determined by comparing the

parity bit of the "A" and the "T."

Command Line - Commands may be strung together in a

single command line of up to 36 characters. The modem

executes the commands in the command string in the

sequence they appear. Spaces inserted into the command

line do not fill space in the modem’s command buffer. A

Carriage Return terminates the command line and causes

the commands to be executed. Register S3 allows the user

to select a character other than a Carriage Return to

terminate the command line.

Re-Execute Last Command - The A/ command re-

executes the last command line. This is the only command

which does not require the "AT" prefix.

Omitted Parameters - Most commands include a

parameter which determines the function setting. When

the command parameter is omitted from the command

string, it is assumed to be a 0.

Result Codes - The modem normally issues a result code

after each action. Result codes may be provided as full

words, one or two digit numeric codes, or may be

disabled. Each result code ends with a Carriage Return

when numeric result codes are chosen. When full word

result codes are chosen, a Line Feed and Carriage Return

precede and follow each result code.

Escape Sequence - A specific character repeated three

times ins succession switches the modem from data mode

to command mode. The character used in this sequence is

defined by register S2. The default sequence is “+++.”

An AT Command must be entered within the period

defined by S12 to complete the switch to command mode.

XECOM

(10)

XE924

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