The reason telecom seems so complicated is, there are so many terms used for the same technology. This is why businesses might want to seek some help when they’re shopping for a business phone or internet service. We have compiled a glossary of commonly used, synonymous, and interrelated telecom terms and acronyms that will give a prospective buyer the clarity they need for such installation.

Phone & Internet Installation Terms and Abbreviations:

The following telecom terminologies might be helpful to know if your business is preparing for a phone or internet

  • ILEC: Incumbent Local Exchange Carrier, the local phone company, Verizon, CenturyLink or AT&T for the majority of the country
  • CLEC: Competitive Local Exchange Carrier, the phone company’s competition, Windstream, XO, Level 3, TelePacific, and Integra are examples of CLECs
  • Direct Rep: Salesperson for an ILEC or CLEC. The primary focus is landing new business, a hunter
  • Sales Engineer: Telecom carrier employee that helps direct reps and agents with interpreting customers’ existing telecom services and designing solutions
  • Account Manager: Representative that works for a telecom company that manages existing accounts vs. bringing in new business, a farmer
  • Offer Management: Telecom carrier employee that prices services on an Individual Case Basis (ICB)
  • IT Consultant: Helps clients with computer equipment, computer networks, email, and software
  • Project Manager: Telecom carrier employee that manages the installation of that company’s services. Coordinates with the customer and the customer’s telephone and IT vendors
  • Cabler: Installs cable and wiring, usually works with a phone vendor
  • Telecom Agent: Independent representative that can resell various carrier services. Compensated by his or her client’s choice of carrier
  • Telecom Consultant: Consultant that works for and is paid by his or her client
  • Phone Vendor: Sells business phone systems
  • PBX: It stands for Private Branch Exchange and is also called the business phone system. Its components include Microcontroller, Interconnecting wires, Control Cards, UPS, and phone sets. PBXs provide many of the same phone features that the phone company offers, including Voicemail, Conference Calling, and Call Transfer
  • Phone Closet: Where a business’s phone service is terminated in an office
  • 66 Block: Where phone lines are terminated in a phone closet
  • Computer Room: Where a business’s computer equipment, servers, routers, etc., are located
  • Cross Connect: When new phone service is ordered, the telephone vendor performs a cross-connect that extends the carrier’s phone lines from the 66 block to the business’s phone system or PBX
  • Demarcation Point: Point that separates the section of telephone wiring that a customer owns and is responsible for and the section that the phone company owns and is responsible for. It is also known as the Minimum Point of Entry (MPOE) or the Network Interface. Demarc is short for Demarcation Point. The phone company usually charges an extra fee if work is required on the business’s side of Demarc. Companies can utilize a phone vendor’s services when work is required on the wiring on their side of the Demarc as an alternative to the phone company.
  • PSTN: The telephone network in a given geographical area is known as the Public Switched Telephone Network (PSTN)


  • Local Loop: The cabling that runs from a carrier’s point of presence to the customer. Usually provided by the incumbent carrier and leased by a competitor. The local loop or last mile also known as the local access is a part of the PSTN.
  • IA Device: Used with integrated T1s and converged services. Separates a customer’s phone and internet services
  • Twisted Copper Pairs: The wiring that a phone line and T1 service are delivered over
  • Bad Pairs: Twisted pairs that need to be repaired before they can be used to deliver service
  • Facilities: The infrastructure that phone lines, DSL, and T1s are delivered over. If there are no available phone lines, there is a shortage of facilities
  • Plug and Play: When the router provided by your internet service provider is pre-programmed with your IP’s, it allows a simpler transition from one provider to another
  • Number Portability: It allows you to keep the same phone numbers if you change service providers, like moving from Qwest to Integra
  • Pic Code: A three-digit number that indicates which long-distance provider’s service is attached to a phone line
  • Inside Wiring: Any wiring, jacks, for instance, on your side of your provider’s Demarc
  • CPE: Customer-provided equipment. These could be phones or computer equipment
  • Circuit ID: If you have a point to point, internet, bonded, or integrated T1 service, you have a circuit ID. It’s included in your order information and written on the circuit termination in your phone closet. You might be asked for your circuit ID if your service goes down and you call your provider’s repair department.

Telecom Terms That are Used Interchangeably Or are Interrelated:

Below are some telecom terms and acronyms which are interchangeable or are interrelated. If you know how these terms are related to one another, it will be easier to make a sound decision.

  • Business phone lines can be referred to as:
    • POTS lines (Plain Old Telephone Service)
    • CO lines (Central Office lines)
    • Analog lines
    • DSOs (Digital Service Zero)
  • Voice over IP related terms: Voice over IP (VoIP) is slowly replacing traditional analog lines
    • Voice over Internet Protocol is the technical term
    • Session Initiated Protocol (SIP): It is the latest voice communication. SIP trunks are dynamic call paths over the internet. Instead of establishing a static voice circuit, which remains in place whether it’s in use or not, when a SIP call is terminated, the bandwidth it required is freed up for other uses
    • Hosted VoIP – VoIP combined with phone equipment
  • Internet connection delivery route terms: There are several routes of internet delivery, some of which are mentioned below:
    • Digital Subscriber Line (DSL),
    • A cable internet connection
    • Broadband, T1, DS1, DS3,
    • OC (optical cable),
    • Fiber
    • GigE
  • Phone Company related terms: Phone companies are also referred to as the following:
    •  Incumbent
    •  Baby Bell
    • An ILEC
    • Regional Bell Operating Company (RBOC)
    • A phone company delivers business phone service to the Demarc
  • Term to be considered while repricing the company’s services
    • QoS: It stands for Quality of Service (QoS). It assures quality voice communication and therefore facilitates VOIP. It’s accomplished by keeping certain measurements in check that can be detrimental to voice communication
    • Class of Service: Think of the internet as a group of roads. Trucks and cars are data traffic. Emergency vehicles are voice and video transmission. Class of Service is the mechanism that gives voice and video (emergency vehicles) priority over other traffic. The benefit of Class of Service is the quality voice and video transmission.
    • Unified Communications: Every form of communication unified at your desktop together is termed Unified Communications. Some of the communications included are Instant Messaging, Voice Communication, High Definition Video Conferencing, Unified Messaging, and Screen Sharing.
      • Example 1: Coworker can Instant Message you answers to the customer’s questions while you are on call with the customer
      •  Example 2: Coworkers can video conference and share their desktops while collaborating on a project simultaneously.
    •  UPS: It stands for Uninterrupted Power Supply. It acts as a temporary power source for computer servers and phone systems if there is an interruption of power.

Business Phone Number Terms & Related Economics:

Some very commonly used terms related to business phone numbers are explained below. They are used by most businesses and are therefore, important to understand:

1. DID’s:

It stands for Direct Inward Dialing phone numbers. These are used with a PRI class of services such as PRI, voice T1, or an integrated T1 with PRI capabilities. With a PRI, you have 23 channels for phone calls that are shared by multiple users. Each employee might require his own number but doesn’t need his own phone line because not all employees are on the phone simultaneously.

It’s also a question of economics. A typical POTS line costs $40 a month, and if you have 12 or so, it’s more economical to have a $500 a month PRI. For example, car dealerships employ many people who need a phone number but don’t require to spend a lot of time on the phone.

Business Phone Number Terms & Related Economics

If there are 40 employees, 40 business lines would cost about $1600 a month. That doesn’t count all the other lines required for faxing and alarms. Most of those lines would hardly be used. A PRI with 23 channels and 100 DID’s would cost less than $600 a month, and the 23 channels offered would be more than sufficient to handle the call quantity.

DID’s are offered by every major provider, like Qwest, AT&T, and Verizon, and most competitive providers like Integra, TW Telecom, and XO.

2. Porting:

Number porting provides mobility of phone numbers from one provider to another. It makes the telecommunications industry competitive. No established business would go for the savings using a cheaper plan by changing providers if they had to change their phone numbers in the process. However, number porting allows businesses to keep the same number while changing.

Number porting is one of the main sticking points when moving from one phone service provider to another. Every carrier has its own time schedule for porting, and if something goes wrong in the order process, the porting clock has to be restarted. Phone numbers can be ported from incumbent carriers, like Qwest, to competitive providers, like Integra, or vice versa.

3. 4 Digit Dialing:

This could be three-digit or five-digit or any number of digits actually, but it’s a term used to describe the ability to dial an extension to reach a coworker, instead of the full phone number, inside an office or between branches. It is a function of a phone system or PBX. With VoIP, this set up can eliminate toll charges between remote offices.

4. Number Spoofing:

The practice of making a phone call appears to be originating from a location other than the one where it was actually placed. Some call centers use this to make phone calls appear local, so they’re more likely to be answered. It has been made possible with the use of VoIP.


These are Area code and prefix related terms. NPA is the area code, and NXX is the prefix.

Process of Installation of Business Phone & Internet Services:

As you can tell, a lot of different telecom terms mean the same thing or are interrelated. Unfortunately, different members of the telecom community use different terminology. As a layperson or civilian, you might learn a few terms only, but there can be a situation when you are confronted with a dozen others you’re unfamiliar with.

Therefore, it is essential to understand the process of installation. It brings a lot more clarity and helps you understand the applications of these terms. Below, we have mentioned a simplistic step by step process that uses many interrelated or synonymous terms. However, once the process is known, it becomes easier to understand the terms:

  1.  A business’s phone vendor extends the Phone Company’s service to a 66 Block, or Punch Down Block and from there to a PBX (Private Branch Exchange) or a Key System or, more simply, a business phone system
  2.  The Business Phone System is connected using Cat5 (Category 5) cabling, or twisted pair. If you are combining your voice and data networks: Ethernet, 10 BASE-T, or even 100BASE-TX.
  3.  Your desk phone, or Station, or End Set plugs into a phone jack, also known as an RJ11 (Registered Jack 11). The number after RJ starts at 11 and goes up from there. It is determined by the number of phone or data lines that can be connected.

In Conclusion

We hope that these telecom terminologies and the process helps you in shopping for business phone and internet services. If you still feel unsure, another way is to let CarrierBid shop the services for you.

The professionals at CarrierBid are all highly-trained telecom consultants. They’ll sift through all the available carriers and technologies and find you the best solution and price possible. Best of all, there is no fee for our service; ultimately, we’re compensated by the carrier of your choice.

If you would like CarrierBid’s help to make your telecom installations go as smoothly as possible, please contact us today or complete the web form on the right side of this page.

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