0049-1800-xxx 326X V.34, V.34-SDC and V.32bis Series Modem – USER’S GUIDE 02/23/2010
Rev. A
Page 67
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205
set
the same
in both modems.
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The modem uses the adaptive rate feature in the V.34 Auto modulation mode. This ensures
maximum throughput when line quality is poor.
Bandwidth On Demand
Bandwidth on demand is often required to support sporadic peak loads. With the SDC modem, you
can ensure full network availability and performance at low dial-up line costs, without having to
prioritize users or applications.
Figure 4-4 shows a point-to-point digital link with Raymar-Telenetics 35XX DSU/CSUs connecting
two routers over a DDS circuit. The SDC modems are also connected directly to the routers. During
peak network access periods, the router is configured to signal the SDC modem to establish a dial
connection through the PSTN. Users transparently bypass the digital link, using the 326XFAST-
SDC PSTN link to continue data transmission. As bandwidth demands subside, the dial call is
dropped, and transmission resumes over the DDS link.
The SDC modem supports all industry-standard ACUs (AT, V.25bis, DTR dialing, and LPDA-2).
Bandwidth on demand can be initiated/terminated under the control of the nodal equipment by a
secondary port.
NOTE
: Nodal equipment must be configured for secondary port restoral/bandwidth
on demand operation. Refer to the nodal equipment documentation for instructions on configuring
for this application.
Select SDC Option Set 3
for a bandwidth on demand application. All operational information
described in the preceding section, “SDC Option Set 3 – Sync Dial Only”, applies to this application.
