Abstract: A receipt generator which produces written receipts at locations remote to the location of use for a conventional charge-card activated system is disclosed. The charge-card activated system provides a telecommunications service and maintains billing records which are supplied at predetermined intervals, such as daily, to a receipt transmission computer. The receipt transmission computer communicates with a personal profile database that associates charge-card numbers with phone numbers assigned to the remote locations. Printing devices, such as facsimile machines, couple to phone lines at these remote locations. The receipt transmission computer identifies, through an examination of charge-card identifiers, particular ones of the billing records for which personal profile database entries exist. The receipt transmission computer then formats a text file for such records.

Abstract: An interface circuit which adapts an existing telecommunications device, such as a facsimile machine, to successfully operate through an existing cellular mobile radiotelephone. No significant modifications are required of the telecommunications device or of the cellular mobile radiotelephone. The interface circuit includes circuitry to convert a two-wire communication interface of the telecommunications device into a four-wire communication interface required by the cellular mobile radiotelephone. This circuitry includes a received signal altering circuit which permits controlling side tone cancellation independently of transmitted and received signal gain control. In addition, the interface circuit includes a switchhook status detector which monitors the switchhook state of the telecommunications device to control muting in the cellular mobile radiotelephone.