Description
The M-993 is a monolithic CMOS integrated circuit designed to generate multifrequency (MF) tone pairs for use in trunk signaling. The tones generated conform to CCITT R1 signal recommendations and to AT&T MF standards. The M-993 permits design engineers to implement a highly accurate MF sender with a minimum of space, power, and added components. The accuracy of the tone frequencies is assured through use of an easily obtained 3.58 MHz color burst crystal or an external 3.58 MHz clock source.

Features
• Generates standard CCITT R1 MF tones
• Digital input control
• Linear (analog) output
• Power output capable of driving standard line
• 14-pin DIP
• Single 5-Volt supply
• Inexpensive 3.58 MHz time base

Applications
• Telephone systems
• Test equipment