Here are definitions of terms I use on this website as I understand them. Some are probably Telecom slang.

Bandwidth - The rate of speed on a wire, fiber or carrier wave. For example: My Cable Internet Service provider provides 3 Megabits per seconds (Mbps) up and 5 Mbps down. That is 3 Mbps of Bandwidth up. If I want 1 Mbps for data traffic that leaves 2 Mbps of available bandwidth for voice traffic. If a phone uses 87.2 Kpbs on a wire or fiber for a VoIP call, that is 87.2 Kpbs of bandwidth used.

Duplex - Two way at a time communications (need for voice). Ex: Ethernet switches are duplex.

CallP - Short hand notation for call processing: the ability of a the equipment to process call requests from the users.

G.711 - Codec for voice and fax IP phone calls. Standard telephone service 64K PCM + approximately 24K of overhead for IP. Total bandwidth used is approx. 87.2. Kbps

G.729 - Codec for VoIP phone calls. Compressed voice to 8K + approximately 24K of overhead for IP. Total bandwidth used is approx. 31.2 Kbps.

IP PBX - A PBX that utilizes VoIP as its primary way of making calls.

Micro Computer - Personal Computer. The other computer types are "mini" and "mainframe". The name Microsoft came because they create software for micro computers.

Micro PBX - An IP PBX built on a micro computer (PC) platform.

PBX - Private Branch Exchange is started out as an automatic telephone switch for an office that replaced the old-fashion switch board and operator and has expanded to follow the user anywhere.

Port Monitoring/Mirroring - The ability of an Ethernet switch to copy the data traffic being transmitted on one or more ports and send that data to another port. Used primarily for debugging using Wireshark.

Simplex - One way at a time communications. Ex: Like a narrow bridge that can only handle cars going in one direction at a time. Ethernet hubs are simplex.

muPBX - mu(µ) in physics is 10E-6 or Micro. Therefore, muPBX = Micro PBX.

VoIP - Voice over IP.


ATA - Analog Telephone Adapter - Used for converting VoIP for standard telephones or fax machines.

CAS - Channel Associated Signaling

CPS - Call Per Second

DAHDI - Digium Asterisk Hardware Device Interface

DID - Direct Inward Dialing

DIY - Do It Yourself

FXS - Foreign Exchange Station - User side of the DS0.

FXO - Foreign Exchange Office - Provider side of the DS0.

IP - Internet Protocol

IVR - Interactive Voice Response

K - Kilo (1,000) - used as an abbreviation for Kbps.

Kbps - Kilobits per second.

KBps - Kilobytes per second.

M - Mega (1,000,000) - used as an abbreviation for Mbps.

Mbps - Megabits per second.

MBps - Megabytes per second.

MOH - Music On Hold

NAT - Network Address Translation

PBX - Private Branch Exchange.

PCM - Pulse Code Modulation.

POE - Power Over Ethernet. Used to supply power to VoIP phones so you don't need to plug the phone into a wall socket.

POTS - Plain Old Telephone Service. The telephone line to your house from the Local Service Provider (SWB, AT&T, Verizon).

PSTN - Public Switched Telephone Network

RTP - Real-time Transport Protocol

RTCP - RTP Control Protocol

SBC - Session Boarder Controller

SIP - Session Initiation Protocol

SSH - Secure SHell

µ - mu - The 12th letter of the Greek alphabet: /micro/ prefix denoting division by 10^6

VAD - Voice Activation Detection. I.e., Silence suppression.

VoIP - Voice over IP

Menu [toggle]