This article describes how two FX631 low-voltage (Subscriber Pulse Metering) SPM detector microcircuits can be used, with additional external filter components, to detect both the 12kHz SPM and the 18kHz security tones employed in the French payphone/cardphone system.
Please login or register with us to view this article>>
Registered already? Login to view complete content.
If you have already registered on the following websites, please log in using your email address and password
eeForum: Demystifying Vietnam What does Vietnam offer that a rising number of top-tier semiconductor companies are setting up and expanding operations there?