CAI JINYONG
2018-3-30
CHONGHAN CH-M4 WIRELESS MODEM USER MANUAL
页
8
1.4.
Products List
Product
Description
CH-M3G2M6
GPRS GSM850,EGSM900,DCS1800,PCS1900
RS232/RS485/TTL
1.5.
Presentation Rules
The AT commands ignore case. For recognizable, the lowercase for input and uppercase for
respond. For example:
at<CR>
// input command
OK
// device response
The send mode support all character send and receive, other mode only below valid:
Type
Value
Describe
Printable
0x20 ~ 0xFE
<0x20> … <0xFE>
Carriage Return
0x0D
<CR>
Line Feed
0x0A
<IF>
transmit
0x1A
<CTRL+Z>
Escape
0x1B
<ESC>
1.6.
AT Command Syntax
at+xxx=?<CR>
// returns the list of parameters and value
ranges
at+xxx=<…><CR>
// sets user-definable parameter values
at+xxx?<CR>
// returns the currently set value
at+xxx<CR>
// execution command
Note: the AT command not case-sensitive, prefix by at and terminate by
<CR>.
2.
Introduction
With the development of wireless communication technologies, wireless products are being
adopted in numerous industrial and civilian fields. Shenzhen Chonghan Co., Ltd. a leader of wireless
communication equipment manufacturer releases the CH-M4 Series Wireless Modems, which
support various frequency bands of GPRS, and provide industrial terminal solutions for 2.5G/2.75G
communication. As a wireless modem, it support AT command set via RS-232/RS-485 interface.
CH-M4 series wireless modem adopts industrial level modules, specially designed for the
complicated industrial environment which compatible with EMC, and will be your best choose of
