September 2008
Intermediate to advanced
550 pages
18h 10m
English
Content preview from VoIP Voice and Fax Signal ProcessingBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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13.4 TELEPHONE LINE MONITOR FOR TONES AND TIMING CHARACTERISTICS
VoIP gateway may be used with multiple country phones. Multiple country phones and interfaces will have different impediments. A telephone line monitor monitors the line without loading and helps in measuring various parameters such as hook-status, battery voltages, ring, tones, loading effects with multiple parallel phones, DTMF detection and analysis, signal levels, different country frequency-shift keying (FSK), and other call feature signal monitoring. This instrument in addition to the TR-57 measurements can provide several details from the whole call, including call features. Line monitor AI-5120 shown in Fig. 13.1 is from Advent Instruments [www.adventinstruments.com]. Some more details on this instrument are available from the manufacturer webpage.
AI-5120 is a compact device designed for monitoring and analyzing signals present on the telephone line. By sensing the voltage present on the telephone line, it detects and measures ringing, DTMF, pulse dialing, FSK of Bell-202 and V.23 signals, line polarity reversals, and open switching interval (OSI). Working in conjunction with the TRsSim software on a PC, the AI-5120 becomes a useful tool in analyzing and debugging caller ID and short message service (SMS) data transmission. Like an oscilloscope, it can capture and display waveforms showing various signals present on the telephone line. This instrument is used for the applications of
- Testing and troubleshooting ...
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