DESCRIPTION
The SA9401 operates in conjunction with a standard EPROM to generate the system tone plans for the PABX systems of most major countries.
The high level of programmability allows the SA9401 to satisfy a wide variety of tone plans. Furthermore by providing three inputs to select between one of eight tone programs during initialisation, the device effectively facilitates the design of a universally programmable "PABX Processor Card". Because the tone program inputs are latched at the start of each PCM frame the SA9401 minimises the possibility of glitches.
The SA9401 can also generate the PCM Frame synchronising reference signal if required.

FEATURES
■ Generates PBX supervisory tones in PCM format
■ Integrated time slot allocation circuitry
■ No noticeable level changes in tones
■ Frame synch. signal source (internal/ external) selectable
■ Eight tone programs
■ Eight independent PCM tone streams within each program
■ Each of these tone streams selectable from 16 tone blocks
■ Seperate Intrude Tone for each program
■ Choice of clock frequencies
■ Watchdog facility
■ Low power CMOS technology

PROGRAMMABLE FEATURES
■ Tone samples
■ Tone Cadence timing
■ Tone to time-slot mapping
■ Size of tone blocks
■ Intrude tone frequency
■ Intrude tone cadence
■ "silence sample" value