Specifications
AN93
36 Rev. 0.9
+ESA =
A,B,C,D,E,F,G
Synchronous access mode control options
A
– Specifies action taken if an underrun condition occurs during transparent sub-mode
0 = Modem transmits 8-bit SYN sequences (see +ESA[G]) on idle.
B
– Specifies action taken if an underrun condition occurs after a flag during framed sub-
mode
0 = Modem transmits 8-bit HDLC flags on idle.
C
– Specifies action taken if an underrun or overrun condition occurs after a non-flag during
framed sub-mode
0 = Modem transmits abort on underrun in middle of frame.
1 = Modem transmits flag on underrun in middle of frame and notifies host of underrun or
overrun.
D
– Specifies V.34 half duplex operation. This parameter should not be used.
E – Specifies CRC polynomial used while in framed sub-mode
0 = CRC generation checking disable
1 = 16-bit CRC generation and checking is performed by the modem
F – Specifies NRZI encoding and decoding
0 = NRZI encoding and decoding disabled
G – Defines 8-bit SYN
255 = Fixed at 255 (marks)
+FCLASS = X
Class 1 Mode Enable.
X
Mode
0Off
1 Enables support for V.29 Fast Connect mode.
256 SMS mode
+FRM = X
Class 1 Receive Carrier.
X
Mode
2 Detect V.21 (980 Hz) tone for longer than 100 ms, then send answer tone
(2100/2225 Hz) for 200 ms.
95 V.29 short synchronous.
96 V.29 full synchronous.
200 Returns to data mode prepared to receive an SMS message.
+FTM = X
Class 1 Transmit Carrier.
X
Mode
2 Transmit V.21 (980 Hz) tone and detect (2100/2225 Hz). Stop transmit 980 Hz when
(2100/2225 Hz is detected.
53 Same as &T4, but transmit V.29 7200 bps. Data pattern set by S40 register. AT +
FCLASS = 0 must be sent to restore the ISOmodem to normal operation after test.
54 Same as &T4, but transmit V.29 9600 bps. Data pattern set by S40 register. AT +
FCLASS = 0 must be sent to restore the ISOmodem to normal operation after test.
95 V.29 short synchronous.
96 V.29 full synchronous.
201 Returns to data mode prepared to transmit an SMS protocol 1 message.
202 Returns to data mode prepared to transmit an SMS protocol 2 message.
Table 18. Basic AT Command Set (Continued)
Command Action