Common Terms & Concepts Flashcards
ATA
Analog Telephone Adapter
A hardware device that connects traditional analog telephones, fax machines, PBX systems, door alarms, and similar devices to digital systems (or an internet or IP-based telephony network)
DID (or DDI)
rework
Direct Inward Dialing (or Direct Dial-In)
When a telephone service provider connects a block of telephone numbers to a company’s PBX; it allows businesses to set up virtual numbers that can bypass the main reception line and go directly to a desk extension
FXS
Foreign Exchange Subscriber/Station
The interface/port that actually delivers the analog line to the subscriber, delivering the dial tone, battery current, and ring voltage.
FXO
Foreign Exchange Office
The interface/port on the phone or fax machine that receives the analog line; it delivers an on-hook/off-hook indication (loop closure).
Device itself (fax or phone) is often called FXO device
SRST
Survivable Remote Site Telephony
A call processing backup mechanism that allows Cisco IP phones to register to a Cisco router; provides remote site survivability in the event of a WAN outage.
Cisco-proprietary mechanism; part of Cisco Unified Communications Manager (CUCM).
POTS
Plain Old Telephone Service
Analog voice transmission phone system implemented over copper twisted pair wires.
PRI
Primary Rate Interface
A physical connection to the PSTN over a dedicated line that only serves voice transmission.
An ISDN standard for carrying multiple DS0 voice and data transmissions between the network and a user.
LERG
Local Exchange Routing Guide
Database of the first 6 digits of a telephone number, updated on a regular basis, that provides info for routing telephone calls over the PSTN (as well as enabling identification of what local company the number belongs to)
Codec
Short for coder-decoder. Codec converts an audio signal (voice) into compressed digital form ready for transmission, and then back into an uncompressed audio signal for replay.
Almost always provide a compression feature to save network bandwidth; used in VoIP communications, video streaming, and video conferencing.
PBX
Private Branch Exchange
The hardware and/or software that comprises a business telephone system.
IP PBX
Internet Protocol Private Branch Exchange
Internet-enabled PBX technology
AAR
Automated Alternative Routing
A Cisco mechanism that enabled CUCM to automatically reroute calls through the PSTN or other networks using an alternate number when the system blocks a call due to insufficient bandwidth.
The process is transparent for the caller (no need to hang up or redial)
ISDN
Integrated Services Digital Network
A circuit switched telephone network system that transmits both data and voice over standard phone lines.
SIP
Session Initiation Protocol
A signaling protocol for internet conferencing, telephony, and instant messaging. It is a request-response protocol, dealing with requests from clients and responses from servers.
IVR
Interactive Voice Response
A computerized system that allows a person (usually a telephone caller) to select options from a menu using either voice or touch to interface with a computer system.
