0049-1800-xxx 326X V.34, V.34-SDC and V.32bis Series Modem – USER’S GUIDE 02/23/2010
Rev. A
Page 64
of
205
Ensuring Optimum Network Performance in SDC Mode
The following parameters are critical for ensuring optimum network performance:
•
Fast Call (AT
*
FC)
•
DTE Rate (AT
*
DE)
•
Flow (AT
*
FL)
•
TpDlyMin (AT
*
TD)
Table 4-4 shows 326X-SDC option set default settings.
Carefully note the following when configuring the modem for SDC operation:
•
Fast Call.
Both the modems must be configured
the same
in order to connect. If one of the
modems does not support Fast Call, change the default setting to Off.
•
DTE Rate.
For better link utilization and throughput, higher values than the default may be
appropriate. (Refer to the DTE Rate description in Appendix A.) Refer to “Optimizing
Network Performance” in the preceding section for more information.
•
Flow/TpDlyMin.
The default options assume the DTE can accept nondisruptive clock
stoppage. For DTEs that cannot handle Rx/Tx clock stoppage without disrupting data, select
a different option. In this situation, Raymar-Telenetics recommends that the default values
not
be used.
SDC Sample Applications
SDC Option Set 1 – Async Calls to Central Site Using AT ACU
SDC Option Set 1 functions the same as described above for non-SDC modems. Refer to that
section for application examples.
SDC Option Set 2 – Sync Dial A/B Restoral
Single Channel Point-to-Point Digital Link Restoral (via A/B Switch)
When used as a dial backup device for a digital network, the SDC modem provides economical dial
backup and/or disaster recovery, at synchronous speeds matching speeds available on the DDS
circuit.
When used as a restoral device for Raymar-Telenetics and Motorola 35XX DSU/CSUs (Figure 4-1),
select SDC Option Set 2
in the local and remote SDC Modems. This places the modems in external
timing, as digital services typically provide the network timing.