User:Ajoyz/Books/Plain old telephone service

Plain old telephone service

 * Plain old telephone service
 * Dual-tone multi-frequency signaling
 * Current loop
 * Mesh analysis
 * Digital current loop interface
 * Highway Addressable Remote Transducer Protocol
 * Fieldbus Foundation
 * Profibus
 * Two-way radio
 * Traffic light
 * Current source
 * Current-to-voltage converter
 * Duplex (telecommunications)
 * Telephone exchange
 * Fiber-optic communication
 * Public switched telephone network
 * Voice frequency
 * Call-progress tone
 * Dial tone
 * Ringtone
 * BORSCHT
 * Tip and ring
 * Local loop
 * Pulse dialing