USER COST CONTROL SOLUTIONS BASED ON DIALING MANAGEMENT FOR PHONE SYSTEMS
Alin Dan Potorac, Eugen Coca, Iuliana Patentariu · 2003
Abstract. To control some phone services at the subscriber end, especially the money consumer ones, is a permanent challenge. The principles described in the article offer some solutions to deny or to selective lock some types of phone calls. The basic idea is to count the number of dialed digits or to detect first (or second) dialed digit. Digital frequency and period filters are use for that. In this manner the phone call could be stopped if the call number contains a greater number of digits than settled up or if the number contains a certain prefix. Both, pulse and tone dialing technologies were taken into consideration. The solutions could be implemented as microcontroller based systems too.