Specifications

Chapter 4 – Serial Interface Control Commands
Multi-Tech Systems, Inc. AT Commands for EDGE (E1) Modems (S000474A) 68
4.7 AT+ICF Character Framing
Description: AT+ICF controls character framing and parity format used for receiving and transmitting data via
the device's asynchronous serial interface (UART).
The following settings are supported:
• 7 bits, even parity, 1 stop bit (AT+ICF=5,1)
• 7 bits, odd parity, 1 stop bit (AT+ICF=5,0)
• 8 bits, even parity, 1 stop bit (AT+ICF=2,1)
• 8 bits, no parity, 1 stop bit (AT+ICF=3)
• 8 bits, odd parity, 1 stop bit (AT+ICF=2,0)
• 8 bits, no parity, 2 stop bits (AT+ICF=1)
The selected setting is stored in the user defined profile with next AT&W. It will only be used on
next start of the device if configured to use a fixed bit rate; i.e., without autobaud usage. The
autobaud feature (refer AT+IPR) detects bit rate and character framing currently used by a
connected TE. However, this detection suffers some limitations described at Section 4.9.1,
Autobauding.
AT+ICF read command will always show the setting stored in the user defined profile, not a
currently detected character framing.
If the current <format> setting uses no parity (e.g., <format>=3) and AT+ICF is used to switch to
a format with parity (e.g., <format>=2), it is necessary to explicitly set parameter <parity>; e.g.,
AT+ICF=2,1. If not done correctly, the device will respond with "+CME ERROR: invalid index".
This is because for <format>=3, the parameter <parity> is set to the internal value 'no parity'
which is not supported by <format>=2. Please remember that if an optional parameter is omitted
for which no default is stated in this document, the value of the parameter remains unchanged.
If AT+ICF modes 7E1 or 7O1 are set, the parity bit will by default not be transmitted over the air.
If the remote party expects the parity bit to be transmitted, additional settings are required via
AT^STPB.
Syntax: Test Command: AT+ICF=?
Responses: +ICF: (list of supported <format>s), (list of supported <parity>s)
OK
Read Command: AT+ICF?
Responses: +ICF: <format>[, <parity>]
OK
Write Command: AT+ICF=[<format>[, <parity>]]
Responses: OK
ERROR
+CME ERROR:<err>
Parameters: The values can be stored with AT&W.
The values can be displayed with AT&V.
<format> Specifies the character format used for receiving and transmitting.
1 8 data 0 parity 2 stop
2 8 data 1 parity 1 stop
3 8 data 0 parity 1 stop. Default. (This is the default value if the parameter is
omitted. It is also the delivery default value of a parameter which cannot be
restored automatically.
5 7 data 1 parity 1 stop
<parity> Specifies the method of calculating the parity bit, if a parity bit is supported by
<format>. If <format> does not support parity, this parameter has to be omitted.
0 odd
1 even
No
tes:
• This command is not PIN protected.
• This command is supported in airplane mode.