Telenetics 56 - Manual (Page 99)

AT Commands
Page 91
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 Value
<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.
<hd_auto> Specifies whether or not, in V.34 half-duplex operation, additional
procedures besides those specified in § 12/V.34 shall be performed by
the modem when switching from primary channel to secondary channel
operation, and vice versa. This subparameter should not be commanded.
<crc_type> Specifies the CRC polynomial used while operating in Framed sub-Mode.