These systems are low in cost but lack flexibility. Power control is afforded by calling one of these numbers. This system has a low initial cost, can be called using any tone dial phone, but the special dial line adds an extra perpetual monthly cost. In many locations this service is not available or restricted to residential use only. This equipment can not be used with a business line or a standard PBX as the equipment will not pass the distinctive ring patterns.
Power control is accomplished by calling from any location using a standard tone dial phone.
The system monitors each call to the remote site and passes the call as required to the attached telecom equipment or allows for flexible control of power.