Frequently Asked Questions

The model number of your phone system can be found on the Central Control Unit. This box is usually located in the comms room. If it’s a Panasonic telephone system it will start with something like: KX-…

A Private Branch eXchange (PBX) is a telephone exchange or Telephone System that serves a private organisation and performs concentration of central office lines or trunks and provides intercommunication between a number of telephone stations in the organisation. The central office lines provide connections to the Public Switched Telephone Network and the concentration aspect of a PBX permits the shared use of these lines between all stations in the organisation. The intercommunication aspect allows two or more stations to establish telephone or conferencing calls between them without using the central office equipment.

Each PBX-connected station, such as a desk phone, cordless phone, or a fax machine, is often referred to as an extension and has a designated extension telephone number.

When dealing with a Private Branch eXchange (PBX), trunk lines are the phone lines coming into the PBX from a telecom provider (like eir). This differentiates these incoming lines from extension lines that connect the PBX to (usually) individual phone sets. Trunking saves cost, because there are usually fewer trunk lines than extension lines, since it is unusual in most offices to have all extension lines in use for external calls at once. Trunk lines transmit voice and data in formats such as analogue, ISDN or VoIP. Trunk lines that use VoIP are called SIP trunks.

An analogue (PSTN) line is a regular telephone line based on analogue signal transmission, common before the advent of advanced forms of telephony such as Integrated Services Digital Network (ISDN) and Voice over Internet Protocol (VoIP). It remains the basic form of residential and small business service connection to the Public Switched Telephone Network (PSTN) in many parts of the world.

An analogue phone line is limited in terms of features compared to ISDN or VoIP, and is also the most expensive in terms of line rental cost. (Currently €20.96 Ex. VAT per month)

Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video and data over the traditional circuits of the Public Switched Telephone Network. No longer used for data since the advent of DSL broadband, ISDN lines are the most common type of voice lines used by businesses today in Ireland. The ISDN protocol delivers multi-channel, not-over-the-Internet service, powerful call setup and routing features, faster setup and tear down of calls, superior audio fidelity and lower cost compared to analogue PSTN lines. There are three kinds of ISDN lines available in Ireland, defined as Basic Rate Access (BRA), Fractional Rate Access (FRA) and Primary Rate Access (PRA).

A Basic Rate ISDN line provides 2 voice channels when connected to a telephone system. Multiple Basic Rate ISDN lines can be combined to provide 4, 6, or more voice channels if required. (Line rental is currently €32.51 Ex. VAT per month or €16.25 per channel)

A Fractional Rate ISDN line provides 16 voice channels when connected to a telephone system. (Line rental is currently €166.50 Ex. VAT per month or €10.40 per channel)

A Primary Rate ISDN line provides 30 voice channels when connected to a telephone system. (Line rental is currently €277.06 Ex. VAT per month or €9.23 per channel)

SIP trunking is a Voice over Internet Protocol (VoIP) service based on the Session Initiation Protocol (SIP) by which Internet Telephony Service Providers (ITSPs) deliver telephone services to customers equipped with an IP-based Private Branch eXchange (IP-PBX). Basically, telephone lines provided over a broadband connection.
SIP trunks provide all the same features as ISDN trunk lines, powerful call setup and routing, faster setup and tear down of calls, and superior audio fidelity compared to analogue PSTN lines.

While SIP trunks are the most cost effective type of trunk lines available, costing less per channel than ISDN or analogue PSTN lines, usually with free landline calls and low cost mobile rates included, a good quality broadband connection is essential for SIP trunks to be a viable solution for business.

Voice Over Internet Protocol (VoIP) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms commonly associated with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, IP communications, and broadband phone service. The term Internet telephony specifically refers to the provisioning of communications services over the public Internet, rather than via the Public Switched Telephone Network (PSTN).

VoIP systems employ session control and signalling protocols to control the signalling, set-up, and tear-down of calls. They transport audio streams over IP networks using special media delivery protocols that encode voice using audio codecs. Various codecs exist that optimise the media stream based on application requirements and network bandwidth; some implementations rely on narrowband and compressed speech, while others support high fidelity stereo codecs. Some popular codecs include μ-law and a-law versions of G.711, G.722, which is a high-fidelity codec marketed as HD Voice by Polycom, a popular open source voice codec known as iLBC, a codec that only uses 8 Kbit/s each way called G.729, and many others.