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Appendix NHayes Modem AT Command Protocol
405
Modem Settings
When this protocol is used, it is required that the modem connected to the Serial Communications Board be initial-
ized to the following conditions:
Command echo No
Result code display format Numeric format
Speed display, busy/dialling tone detection at
connection
Baud rate display enabled, busy and dialling tone
detection enabled.
Error correction data compression display Error correction/data compression display enabled
MNP setting Error correction provided (auto-reliable mode)
MNP class setting MNP class 4
V.42 compression, Error correction Not enabled
Flow control between terminal modems Not enabled
ER signal control Always ON
Escape code +
Note 1. It is recommended that, in addition to the above settings, the abort timer should be set so that commu-
nications are cut off if a communications error happened due to incidents such as cable disconnection
between the Serial Communications Board and modem. Set the abort timer to 10 minutes for the mo-
dem initialization (specialized) (Sequence No. 560, 570, 580). Refer to modem’s manual for further in-
formation about abort timers.
2. The data format of the modem (baud rate, data length, parity, stop bit) is set by AT commands issued
from a device connected to the modem. Its settings should conform to communications conditions of the
device which issues AT commands. Therefore when communications are made between the modem
and Serial Communications Board, it is required that communications conditions should be set by issu-
ing AT commands from the Serial Communications Board.
3. Modem settings become invalid if the power supply is turned off and must be set again. However, a
memory backup function can be used to protect settings so that even after the power supply to the mo-
dem is turned off, it can communicate with the previous setting conditions.
For Initialize Modem (specialized), the modem initialization command is built in as message data. However, for
Initialize Modem (general-purpose), the command must be specified in PMCR.
Operand 1 #x550 (x: Communications port)
Operand 2 First address for storing initialization command character string C
Operand 3 None
C+0 Number of words from address set for operand 2 to end of data 4 digits BCD
C+1 Number of bytes for send data (initialization command) 4 digits BCD
C+2
:
C+n
Send data (initialization command)
(Fill data to left for odd numbers of bytes)
ASCII
Setting Example for Modem Initialization Command
• MD24FB10V Using Sequence #550 (OMRON)
The following command is set in the words specified by the second operand of PMCR.
ATE0V0X4\V2\N3%C0*C0\X1&M0S26=10
Character string length of modem initialization command (bytes)
Code length of PMCR when it is used (words)
ATE0V0X4\V2\N3%C
0*C0
\X
1&M0
S2
6=10
00320018
Note Turn ON pin 4 of DIP switches SW3 on for this Modem (ER signal always ON).