M-984-02

• Detects single-frequency tones used for error indication and call progress in telephone systems
• Provides detection windows for: 400/425 Hz (Call Progress) 950 Hz (Special and error indication) 1400 Hz (Special and error indication) 1800 Hz (Special and error indication)
• Separate tri-state outputs for each tone window
• Inexpensive 3.58 MHz crystal time base
• Auxiliary 3.58 MHz clock output
• 14-pin DIP package and 16-pin SOIC package
• Single supply 3 to 5 volt (low power CMOS)
• Wide dynamic range (30 dBm)

The M-984-02 Special Information Tone Detector is a monolithic integrated circuit designed to provide reliable detection of many common telephone network status signals. In particular, it detects the signals known as Special Information Tones (SITs) or error tones as defined by the CCITT, and single tones often used as dial tone, audible ringing, and other general progress indications. The M-984-02 uses CMOS switched capacitor filters and a crystal time base to achieve the high stability and accuracy specified. Each tone detection window has an associated output pin,
which can be placed in a high impedance state for use with time-share microcomputer bus applications.

In comparison with the earlier M-984, the M-984-02 has wider acceptance bands for SIT tones to facilitate reception of tape-loop tones, lower power consumption at 5V operation, 3V operation, superior temperature performance, lower cost, and is available in DIP, SOIC, and SOIC tape and reel versions.