Cellular Phone: Motorola MC34118 Application Semiconductor for Featurephone Design With Tone Ringer and Dialer Using Speakerphone IC.pdf

This application of Motorola MC34118 note describes how to add a handset, dialer and tone ringer to the MC34118 speakerphone circuit. Although any one of several speech networks could be used as an interface between the MC34118 and the phone line, this application note covers the case where simplicity and low cost are paramount. A privacy (Mike Mute) function is included, but not pulse dialing, nor line length compensation. Two circuit are developed in this discussion: a line-powered featurephone and one powered from a power supply. The circuits arenearly identical, except for the Tip and Ring interface. Their parameter however, differ noticeably, particularly in the low loop current range. Table of contents for Motorola MC34118:

* MC34118 Description
* Line Powered Featurephone
* Using a Power Supply Instead of Line Power
* Construction Hints.

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