Telenetics V.34-SDC - Manual (Page 80)

4-22 Configuring the Modem
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Configuring the Modem for SDC Operation
You can configure the 326XFAST-SDC Modem for SDC in one of these ways:
• Select Option Set 2, 3, or 4Leased, discussed below
• Configure the modem as follows:
— Select one of the reliable data transfer modes (Reliable, Auto Reliable, or
Speed Auto Reliable).
— Choose an Auto-Call Unit (ACU)—AT, V.25bis, LPDA, or None—using
the ACU Select option, ACU OPT’S category.
— Select a bit-synchronous data format (depending on the ACU type).
Refer to Appendix A for additional information on each of these methods.
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 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,
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.