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Operation
Switched Network Operation
To establish a connection with another modem, use the auto-dial facility of the modem.
Telephone Lines
If the modem is connected to a business telephone system, such as a multi-line key system or PBX,
there can be noise generated by the system that can affect telephone quality. For optimal throughput,
connect the modem to a single switched line that is used by nothing else.
Many telephone companies offer "call waiting" service that alerts you to another call coming in
while you are on the line. Call waiting service can interfere with modem data calls or even
disconnect the modem. In error correction mode the modem will correct data interference caused
by call-waiting, but doing so degrades throughput. If you have call-waiting, you should disable it
while you are on the line to prevent loss of through-put. In some areas, for example, you can disable
call waiting by dialing 70# or *70 on your pushbutton telephone. Verify the call-waiting
numbers with your local telephone company.
The following are examples of commands to send to the modem to disable call waiting for the
duration of a call (the telephone number 555-1234 is provided for example only)
For Touch-Tone dialing:
ATDT*70W5551234
For Both Pulse and Touch-Tone Dialing:
ATD1170W5551234)
Note
After the *70 or 1170 number is dialed, your PSTN should respond with dial tone. Call-
waiting will be disabled for the duration of that call. Once the call is disconnected, call-waiting
will be enabled again. Verify the numbers and their effects with your local telephone company.
Another method is to set your modem to S10=150. This setting lets your modem ignore a brief
cut-off caused by call-waiting, and prevents it from hanging up while on-line.
060R122-000
Issue 15
SpectraComm Dual V.34 Modem
Installation and Operation
Switched Network Operation
3-35
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