TH17714A - Carbon link microphone for modem - Google Patents

Abstract

A modem includes data access management circuitry that arranges data exchange between the computer and the connection device. Alternatively, data is transferred from this data access management circuit to the input of a carbon link microphone circuit. A carbon link microphone circuit includes galvanic isolation circuitry and impedance matching circuitry. The input of the carbon link microphone circuit is therefore converted to a format compatible with the carbon microphones found in handheld phones. Consequently, the output of the carbon link microphone circuit can be connected to a handheld phone.

Claims (1)

1. A carbon microphone coupling device that connects a modem to an audio terminal equipped with a carbon microphone. Such coupling device consists of a junction path to isolate the DC current from the output signal of the modem and an impedance matching path to convert the output impedance of the junction path to the impedance of the carbon microphone. (4 claims, 1 figure)