Glossary Terms for Telecom Services

Every industry has its own language and extensive list of anonyms and terms that make it difficult for the lay person to navigate through. The telecommunications industry is no different. On a daily basis, we help people decipher these terms so that they can simply review their company’s telecom bill. Therefore, I thought it would be a good idea to outline the top 10 terms/acronyms as a resource for future referencing.

CENTREX – Type of telephone line service that includes features on the line like call transfer, call waiting, abbreviated dialing.

CO – Central Office, location of the service providers’ equipment that supplies service to your company

DID – Direct Inward Dialing, type of line that supplies a range of 20, 40 60 or 100 telephone numbers that are similarly numbered and can be programmed for users to have direct lines. Typically used for large companies with several extensions. (i.e. XXX-2473, XXX-2474 etc.)

DIA – Dedicated Internet Access, a service that provides a direct connection between your facility and your Internet Service Provider.

DSL – Digital Subscriber Line, a high-speed internet service connection uses a phone line (Centrex or 1MB) to supply service. Speeds of service vary depending on the distance from your office to the Central Office.

ISDN – Integrated Services Digital Network, an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires. ISDN supports data transfer rates of 64 Kbps (64,000 bits per second).

There are two types of ISDN:

• Basic Rate Interface (BRI) — consists of two 64-Kbps B-channels and one D-channel for transmitting control information.

• Primary Rate Interface (PRI) — consists of 23 B-channels and one D-channel (U.S.) or 30 B-channels and one D-channel (Europe).

PSTN – Public Switched Telephone Network refers to the nationwide telephone system delivering services to home and business.

T-1 or DS1 – A dedicated phone connection supporting data rates of 1.544Mbits per second. A T-1 line consists of 24 individual channels, each of which supports 64Kbits per second. Each 64Kbit/second channel can be configured to carry voice or data traffic. T-1 lines are a popular leased line option for businesses connecting to the Internet.

ISP – Internet Service Provider a company that provides internet service.