0049-1800-xxx 326X V.34, V.34-SDC and V.32bis Series Modem – USER’S GUIDE 02/23/2010
Rev. A
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Option Set 2 – Sync Answering Central Site Without an ACU
Option Set 2 satisfies the needs of a synchronous application where most calls are to a central site (see
Table 4-1).
Because calls are received primarily at the central site, the modem is set to answer calls automatically.
With
DTR
=108.2, the local DTE can control the DTR signal. This allows the local DTE to use DTR
transitions to connect the modem to the central site at the beginning of transmission and disconnect it
when transmission ends.
At the beginning of each connection, the modem negotiates the highest common data rate with the
remote modem. The modem uses the adaptive rate feature in the V.34, V.32bis, or V.32 modulation
modes. This ensures maximum throughput when line quality is poor.
Option Set 3 – Sync Calls to Central Site Using the V.25bis ACU
Option Set 3 satisfies the needs of a synchronous application, where the remote modems originate calls
to a central site (see Table 4-1).
With Option Set 3, the modem originates calls with its V.25bis ACU. The DTR option is set to 108.2 so
that the V.25bis ACU can manipulate the DTR signal. All other options in the ACU OPT’s category are
set for a typical synchronous DTE.
At the beginning of each connection, the modem negotiates the highest common data rate with the
remote modem. The modem uses the adaptive rate feature in the V.34, V.32bis, or V.32 modulation
modes. This ensures maximum throughput when line quality is poor.
Option Set 4 – Async Answering Central Site Without an ACU (Models 3260/62/65/67)
Option Set 4 satisfies the needs of an asynchronous application where most calls are inbound (see Table
4-1).
Because calls are received primarily at the central site, the modem is set to answer calls automatically.
With
DTR
=Discon, the local DTE can control the DTR signal. This allows the local DTE to use DTR
transitions to connect the modem to the central site at the beginning of transmissions and disconnect it
when transmission ends. The DTR signal from the DTE must be high for the modem to auto-answer. If
the DTR signal is low, it does not answer incoming calls.
At the beginning of each connection, the modem negotiates the highest common data rate with the
remote modem. The modem uses the adaptive rate feature in the V.34, V.32bis, or V.32 modulation
modes. This ensures maximum throughput when line quality is poor.
