Telephony services are used to place calls, monitor a call's progress and detect incoming calls on POTS (plain old telephone service) lines. In digital telephony where call control is directed by other means, DTMF dialing and call progress monitoring are required for secondary dialing.
The North American Telephony Platform is used for call control under North American administrations. The International Telephony Platform is used for call control under various International administrations.
When originating a telephone call, call progress tones are generated by the telephone network as the call sequences through the telephone network. The application software uses these conditions to control its actions. The call progress signals include primary and secondary dial tone, busy, congestion, ring back and bong.
Telephone numbers can be dialed with tones (DTMF), pulses or adaptively. Adaptive dialing can be used when the capability of the telephone line is unknown, but tone dialing is preferred. Pulse dialing must be implemented with external hardware, usually a relay in the telephone circuitry.
Caller ID Types I and II are available. Caller ID is a burst of Bell 202/V.23 modulated information generated between the first and second ring. The Caller ID information provides the telephone number and/or name of the calling party.
Ring detection is used to detect valid incoming ring signals. Distinctive ring detection can be used to detect the different ring cadence. Distinctive ringing, an option available from the telephone company, provides several different telephone numbers for a single physical line; incoming calls produce a distinct ring cadence for each dialed number. Data/Facsimile/Voice Distinction is available. Complete data modem, facsimile, speech coder and multimedia systems are available.
VOCAL's embedded software libraries include a complete range of ETSI / ITU / IEEE compliant algorithms, in addition to many other standard and proprietary algorithms. Our software is optimized for execution on ANSI C and leading DSP architectures (TI, ADI, AMD, ARM, MIPS, CEVA, LSI Logic ZSP, etc.). These libraries are modular and can be executed as a single task under a variety of operating systems or standalone with its own microkernel.