[comp.dcom.modems] Telephone system problem with the call signals.

mshiels@tmsoft.uucp (Michael A. Shiels) (11/17/90)

Does anyone know if any of the modem manufacturers are starting to add
support for identifying the 3 signals that most phone companies use before
recordings etc.  For things like line problems, out of service, changed number
etc?

dave@westmark.WESTMARK.COM (Dave Levenson) (11/19/90)

In article <jk9g8765t@tmsoft.uucp>, mshiels@tmsoft.uucp (Michael A. Shiels) writes:
> Does anyone know if any of the modem manufacturers are starting to add
> support for identifying the 3 signals that most phone companies use before
> recordings etc.  For things like line problems, out of service, changed number
> etc?


The BEST SmartOne modems detect these tones (called SIT or Special
Information Tones) and treat any combination of them as the same as
fast-busy.  They apparently don't distinguish between the several
defined sets of frequency and duration which have slightly different
meanings in the telephone network.

-- 
Dave Levenson			Internet: dave@westmark.com
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