Comtrol AT Command Set Rev A - Manual (Page 100)

AT Commands Reference Manual
Conexant 100722B
3-74
3.2.8 Synchronous Access Mode Commands
Three commands support Synchronous Access Mode:
+ES Enables and disables Synchronous Access Mode in the client
or central site modem (see 0)
+ESA Configures the operation of the Synchronous Access Submode
+ITF Selects Transmit Flow Control Thresholds
Enabling Synchronous Access Mode enables the use of the 8-bit command characters
defined in Table 9/V.80 of the Draft ITU-T Recommendation V.80 (DATA
COMMUNICATION OVER THE TELEPHONE NETWORK; In-Band DCE Control
and Synchronous Data Modes for Asynchronous DTE).
+ESA - Configure Synchronous Access Submode
The operation of the Synchronous Access sub-Mode is configured by the +ESA
parameter.
This extended-format compound parameter is used to control the manner of operation of
the Synchronous Access Mode in the modem. It accepts six numeric subparameters:
Syntax
+ESA=[<trans_idle>[,<framed_idle>[,<framed_un_ov>[,<hd_auto>[,<crc_type>[,<
nrzi_en>[,<syn1>[,<syn2>]]]]]]]]
Defined Values
<trans_idle> Specifies the bit sequence transmitted by the modem when a
transmit data buffer underrun condition occurs, while
operating in Transparent sub-Mode. The options are:
0 In Transparent sub-Mode, modem transmits 8-bit
SYN sequence on idle. Modem receiver does not
hunt for synchronization sequence (default and
fixed).
<framed_idle> Specifies the bit sequence transmitted by the modem when a
transmit data buffer underrun condition occurs immediately
after a flag, while operating in Framed sub-Mode. The options
are:
0 In Framed sub-Mode, modem transmits HDLC
flags on idle (default and fixed).
<framed_un_ov> Specifies the actions undertaken by the modem when a
transmit data buffer underrun or overrun condition occurs
immediately after a non-flag octet, while operating in Framed
sub-Mode.
0 In Framed sub-Mode, modem transmits abort on
underrun in middle of frame (default).
1 In Framed sub-Mode, DCE transmits a flag on
underrun in middle of frame, and notifies DTE of
underrun or overrun.