Filter
Top Products
Appendix NHayes Modem AT Command Protocol
409
Setting Example
When send data is THIS IS SAMPLE.
Character string length of send data sent to modem (bytes)
Code length of PMCR when it is used (words)
00140009 5448
T H
4953
I S
2049
I
5320
S
5341
S A
4D50
M P
4C45
L E
A maximum of 200 bytes (including the CR) can be received. When the received data is RETURN OK, the content
stored in the receive words is as follows:
Length of received character string (words)
0006 5245
R E
5455
T U
524E
R N
204F
O
4B00
K
Note An error will occur is the reception data is not received within 90 seconds after the data is sent.
Escape Mode
Shifting to the escape mode can be made using sequence No. 554. No setting is necessary for this sequence.
Note The character string to shift the online mode to the escape mode (i.e., the escape code) is ‘+’ for modem
settings.
Hang Up Command
The hang up command (to disconnect the line) can be executed using sequence No. 555. No setting is necessary
for this sequence.
Communication Errors
Three result codes are monitored after an AT command is sent to the modem. When a result code is returned, it will
be checked. If the code is not the normal result code (“OK”, “CONNECT 9600/REL4”, “CONNECT 2400/REL4”, in
words), after a fixed time of waiting to send, the following retry processing will be repeated 2 times to send the AT
command again and waiting for another result code.
The receive monitoring time and send wait time for each sequence are shown below.
Sequence
No.
Sequence name Receive monitoring time Send wait time for retries
#550 Initialize modem (general-purpose) 10 s 1 s
#560 Initialize modem (specialized) 10 s 1 s
#570
#580
#561 Dial 90 s 90 s
#571
#581
#552 Password None 3 s
#553 Data send/receive (general-purpose) 90 s None
#554 Escape 10 s 1.5 s (after first try)
#555 Hang up 10 s 1.5 s (after first try)
#562 Initialize and dial 90s Initializing: 1 s
Dialling: 90 s
#572
#582
#590 Escape and hang up 10 s 1.5 s (after first try)