Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 125)

AN93
Rev. 1.3 125
5.13. EPOS (Electronic Point of Sale) Applications
EPOS applications are discussed in "Appendix A—EPOS Applications" on page 257.
5.13.1. EPOS Fast Connect
The ISOmodem supports several fast connect modes of operation to reduce the time of a connect sequence in
originate mode.
5.13.2. EPOS V.29 Fast Connect
In addition to the low modulation speed fast-connect modes, the modem (only Si2493/57/34/15) also supports a
fast-connect mode based on the 9600 bps V.29 fax modulation standard. V.29 Fast Connect is available as a
patch. Please contact Silicon Laboratories for additional details.
5.14. Legacy Synchronous DCE Mode/V.80 Synchronous Access Mode
The ISOmodem supports two different DTE interfaces to implement an Asynchronous DTE to Synchronous DCE
conversion. Table 84 provides high-level options to choose between the Legacy Synchronous DCE Mode and the
newer V.80 synchronous access mode.
The synchronous access mode has more features than the Legacy Synchronous DCE Mode. For new designs,
use of the newer synchronous access mode interface is recommended. Otherwise, existing software written with
the Legacy Synchronous DCE Mode interface can still be used as long as the AT+ES command settings are not
changed from the default value.
5.15. V.80 Mode
As shown in Table 85, the synchronous access mode is chosen by using the AT+ES=6,,8 command setting.
When using the synchronous access mode, it is expected that the AT\N0 command will be used to disable all other
error correction protocols that may interfere with V.80 synchronous access mode operation.
The V.80 Mode has two distinct submodes. Switching between these two submodes can be accomplished within
the confines of the same connection through the use of In-Band commands. The submodes are:
 Transparent Submode
 Framed Submode
The Transparent Submode creates a direct bit-by-bit translation from the DTE to and from the DCE. Any
application that requires a method of reconstructing a serial bit-stream at the DCE can use the Transparent Sub-
mode.
The Framed Sub-mode represents data at the DCE in HDLC/SDLC frames. This submode is typically used in
point-of-sale terminals. A common feature used in conjunction with the Framed Submode is the use of the 16-bit
CRC. When used with the CRC option, the Framed Submode can be used in the same applications currently using
the Legacy Synchronous DCE Mode.
Table 84. Synchronous Mode Overview
Mode U Register AT+ES
Settings
Neither U7A [2] = 0 +ES = D,,D
Legacy Synchronous
DCE Mode
U7A [2] = 1 +ES = D,,D
Synchronous Access
Mode
+ES = 6,,8