1. DTMF stands for:
(A) Digital Telephony Multiple Frequency
(B) Dial Tone Master Frequency
(C) Dual-Tone Multi Frequency
(D) Digital Trunk Master Frequency
2. PSTN stands for:
(A) Primary Service Telephone Network
(B) Private Switched Telephone Network
(C) Public Switched Telephone Network
(D) Primary Service Telephone Numbers
3. POTS stands for:
(A) Plain Old Telephone Service
(B) Primary Office Telephone Service
(C) Primary Operational Test System
(D) Private Office Telephone System
4. Central offices are connected by:
(A) Trunk lines
(B) Local loops
(C) Both a and b
(D) None of the above
5. DC current flows through a telephone:
(A) When it is on hook
(B) Only when it is ringing
(C) As long as it is attached to a local loop
(D) When it is off hook