Marketing control program
Marking and screening telephone calls
Masked phone service with mask phone number
Mass polling system
Master unlock circuit for a feature telephone station...
Matrix card test circuit
Means and apparatus for control of remote electrical devices
Means for activating and controlling a remote meter reading...
Means for and methods of real time detection of fraud, lack...
Means for identifying subscriber lines
Means for suppressing the ground currents
Measuring and monitoring system
Measuring speech quality
Mechanical communications switchboard
Mechanical device for limiting duration of a telephone...
Mechanical storage means for repertory dialer
Mechanism for controllably enabling test set to assert...
Mechanism for opening and closing an appliance
Mechanism to facilitate single-number for voice and...
Mechanism to support multiple versions of toll free service