Research & Development
APPENDIX_C
uModem AT Command Reference Manual
1. Special Key
Command
Options Function & Description
Ref.
A/
Re-execute the last command once.
A>
Re-execute the last command once or
repeat the last call up to 9 times. (See also
S8)
<any key>
Terminate current connection attempt when
entered in handshaking state.
+++
Escape sequence code, entered in data
state, wait for modem to return to on line
command mode.
2. Basic AT Command Sets
All the Following Commands Require an “AT” Prefix:
Command
Options Function & Description
Ref.
A
Go on-line in answer mode. (See also
S39.2, S43.6)
Bn Handshake
option.
S28.7
B0 *
Select CCITT V.22 for 1200 bps
B1
Select Bell 212A for 1200 bps
communication.
D
s
Dial s (numbers and options) that follow
(see also S38.0, S35.4). The options of s
are listed as follows:
0-9, A, B,
C,D #, *
Digits for dialing
P
Pulse
dialing
S23.1
T
Tone
dialing
S23.1
,
Pause for a time specified in S8.
Remaining digits will be dialed as in-band
DTMF.
;
Return to command state after dialing
!
Hook
flash
@
Wait for a 5 second silence before
proceeding , otherwise return NO
ANSWER
R
Reverse handshake (go on-line in Answer
mode)
S17.5
W
Wait for the second dial tone. Remaining
digits will be dialed as in-band DTMF
DL
Dials the last-dialed number
DS
n
n=0-3
Dial the number stored in non-volatile
RAM at location 'n'
S44.3
E
n
Command mode local echo of keyboard
commands
S23.0
Page
14
of
14
Revision 1.0
2003/6 From 3JTech