Useful definitions relating to telephony for SMEs

ADSL (Asymmetric Digital Subscriber Line) Technology that allows for a one to one digital connection on a pair of copper high-speed wires (up to 8 Mbps for receiving data and 640 Kbps for transmission). This technology allows the telephone to be in use while being connected to the Internet. The maximum distance between the subscriber and the local exchange must not exceed 5 km.

AOCD / AOCE Display call cost during and at the end of a call. The user is aware of the cost of their call during and at the end of the call.

Backbone IP network operator and can guarantee bandwidth and QoS (Quality of Service).

Bluetooth System based on short-range radio technology to provide a wireless connection between mobile phones, laptops, handheld devices and other mobile devices. Used worldwide, Bluetooth can connect up to 8 devices simultaneously and transmits both voice and data from one device to another over a distance of 10 meters.

Bps (bits per second) Unit of measure of transmission rate (modem, leased line, etc.).

Bus SO Local ISND network enabling the connection of up to 4 terminals and 4 more if they are powered locally. Different types of terminals (e.g. telephone, fax, computer…) can be connected on the same bus.

Call waiting Making it possible to switch between two telephone calls.

Channel B Channel switched in circuit mode. For both the basic connection and the primary connection, its capacity is 64 kbit/s. The base connection has 2 and the primary connection 30.

Channel D Channel reserved for signaling (making calls and hanging up, call identification, supplementary services, short message…) and also allows the transmission of data packets.

CLIP / CLIR Authorization/restriction of displaying of the caller’s number to who has been called. This special service allows the caller to allow or keep secret the identification of the data connection.

COLP / COLR Authorization/restriction of displaying the called number for the caller. This special service allows the recipient to authorize or deny the display of their connection number.

CTI Computer Telephony Integration.

DDI (Direct selection ISDN) Private telephone exchanges have the ability to assign numbers (extension) for each internal telephone. To make a direct call to one of these devices, the telephone number (6 numbers) of the private exchange and then the extension number is usually dialed. This allows the caller to avoid going through the helpline.

DECT (Digital European Cordless Telephone) Technology adapted to wireless phones with the latest scanning and data compression technologies.

DSL – xDSL Technologies that allow a high-speed one to one connection on a pair of copper wires (telephone line). They allow you to share a phone line for voice and data (you can use the telephone and be connected to the Internet at the same time.) For data, we get high rates that can be asymmetric (ADSL/VDSL) or symmetric (SDSL or SHDSL).

DSP Digital Signal Processor: Microprocessor optimized for processing digital signal.

Detailed billing List of all calls with each number called. Each call is described by its pulse number, the duration of the call, the date and time of call termination.

Fax Server A Fax Server enables the centralization of fax numbers on a pc from where the fax may be resent by email or printed.

GPRS (Global Packet Radio Services) Wireless technology for transmitting information in packets as on the Internet. The transmission rate can reach 115 kbps.

Hand-over DECT or Wi-Fi Process that maintains a call on a mobile DECT or WiFi terminal during movement from one antenna to another.

IBPT Belgian Institute of Postal Services and Telecommunications.

ISDN (ISDN- Digital Network Integration Services) Telecommunications network that allows the transport of digital data from end to end and provides multiple remote services and support services.

LAN (Local Area Network) Private network of a company or individual.

LCR (Least-Cost Routing) Software to route calls to the best operator, according to cost and quality of the traffic that is dedicated to voice.

Modem (modulator-demodulator) Equipment for the modulation and demodulation of a signal, used for a temporary Internet connection or between two computers.

MMC (Mitel Mobile Client) AMC transforms your Smartphone into a SIP terminal that is completely controlled by the MIVoice Office 400 platform.

MSN (Multiple Subscriber Number) This complimentary service to ISDN lets you directly contact the desired number, avoiding routing through the helpline. Each terminal has a 6 digit telephone number.

NT (Terminal Equipment – Digital Termination Network) This equipment performs the functions of transmission, power supply and operation for basic access. It only offers digital access, meaning that only ISDN devices may be connected to it.

PABX (Private Automatic Branch Exchange) The company’s private branch exchange.

PoE (Power over Ethernet) Power over Ethernet provides power to IP devices from the Ethernet network. Each PoE port can power a compatible PoE device. Example: feeds each individual SIP telephone.

PRA (Primary connection “30 B + D”) This voice and/or data connection corresponds to the 2 Mbits/s telephone connection. Like the latter, it offers 30 communication routes (30 B channels), but these are digital routes (64 kbit/s each), for a total payload of 1920 kbit/s.

PTSN Public Switched Telephone Network. All functional units that establish telephone circuits between two telephonic devices.


Roaming Capacity for the mobile subscriber to call or be called in many countries, using the SIM card and being charged by their operator. This is made possible because of “roaming agreements” made between the various operators.

Router A router is a computer element linking the internal network (LAN) with an external network (WAN) such as the Internet or a private network.

SIM (Subscriber Identification Module) SIM Card: electronic chip inserted into a mobile phone for user identification. This card belongs to the user.

SIP operator A SIP operator provides an account that allows VoIP calls. It channels communications by broadband DSL lines to and from your VoIP telephone exchange. To do this, it is necessary to have a sufficient Internet connection.

Softphone A softphone is a piece of software that allows you to call directly from your computer.

TA Terminal adapter. It ensures the adaptation of non-ISDN interfaces (analog equipment, X21, X25) to the SO bus of the base ISDN connection to allow the establishment and transmission of calls.

TAPI Telephony Application Programming Interface. Protocol belonging to Microsoft.

UMTS (Universal Mobile Telecommunications System) New generation (3G) of digital mobile phone incorporating multimedia features for data traffic other than voice to broadband (theoretically up to 2 mbps, in reality from 64 kbit/s to 384 kbit/s).

VoIP – Voice Over Internet Protocol Voice over IP. Technique which allows the transit of voice over IP.

VPN (Virtual Private Network) Virtual link between two sites simulating a single site.

WAN (Wide Area Network) Internet network outside of the LAN.