PBX Interface Standards

By Jelani Harper
Updated: March 28, 2011

A number of interface standards for Private Branch Exchanges (PBXs)—the central component in Voice over Internet Protocol (VoIP) equipment, a computerized, call routing and messaging system with internet capability and more—have been developed in a relatively short amount of time. As needs for PBXs have changed, so have their interface standards, both of which reflect the universal need for modern, efficient communication. Presently, PBX standards have evolved towards unified communications (UC), a single system which connects wireless and wired phones, email, instant messaging and voicemail while granting users presence status.

With current VoIP equipment capable of handling upwards of over 100 calls concurrently, accessibility to PBX information is at a premium for many enterprises which lack the time to do so in individual applications. Interface standards for collecting data from PBX were created to meet these needs. Several interfaces (which were traditionally used to print every call via printer) are used to connect various applications which access data, while network ports such as TCP and UDP can stream information to applications as well.

Other PBX standards have evolved to meet a variety of needs, such as Internet Protocol (IP) standards H.323 and SIP. Originally used to connect IP phones to PBXs, these interfaces are not only employed to connect PBXs to each other (in addition to IAX protocols, which transmit voice and video calls) but also to interface PBXs to trunk lines. MGCP and Inter-Asterisk eXchange are examples of other protocols which operate via IP with network provider support. ISDN, which has become one of the most common digital standards for fixed telephony equipment, was also created to connect PBXs to trunk lines. This interface is able to supply 2 to 30 circuit capability and is commonly carried on T1 or E1 connectors.

The original use of PBX standards was to connect telephone extensions to the branch. While plain old telephone service (POTS), the common two wire interface found in most homes which can also connect PBXs to trunk lines--although here it’s limited in its effectiveness for performing basic functions such as detecting incoming calls while making outgoing ones--was certainly employed, manufacturers often utilized defined protocols that required their specific proprietary sets. Users benefited by obtaining function buttons specific to their branch features, while DECT became the standard for cordless phone connection.

Despite standards later created for more complex needs such as inter-branch connectivity and data collection, some of the latest VoIP technology specifically aimed towards providing UC access to users continues to support basic standards such as POTS, in addition to more versatile standards including ISDN, H.323, T.38 and SuperG3FAX in order to provide a truly unified platform—which is what PBX interface standards are evolving towards.
 

Featured Research
  • Your Phone System and Your Bottom Line

    Businesses have been using phones to drive increases to their bottom lines for almost a century now. Telephony, much like the rest of the business world, has seen drastic changes with the increase in technological advancement. Voice Over Internet Protocol (VoIP), has enabled companies to connect with consumers at levels that have been seen as unheard of before. And trust us when we say this, it is doing wonders for the bottom line. more

  • 2017 Phone Systems Checklist

    As you are well aware, we are living in an age of extreme technological growth. With this, an understatement might be that phone systems have changed a bit over the last decade. If you are in the market for a new phone system, it is absolutely essential for you to have knowledge of this vast sector and just what exactly you need in order to have your business succeed. more

  • VoIP vs. VoPI

    Are you searching around for an upgrade to your current phone system? If so, you've mostly likely heard of VoIP, but do you know about VoPI? Lately, there has been a lot of conversation around what the difference is between the two systems. Most of this conversation centers around security, as both of these systems, operate over the internet versus the traditional phone lines. more

  • Why You Need Mobile VoIP

    Mobile VoIP is growing at an exponential rate and can help your company reduce costs, improve communications, and drive increased employee satisfaction and loyalty. If what was just mentioned above sounds like it would be good for your business (it is), download our latest guide Why You Need Mobile VoIP to learn even more reasons why you need to make the switch today! more

  • How You Can Stop VoIP Eavesdropping

    In today’s modern technological world we face cyber threats on an almost daily basis. This rings true when switching phone systems to VoIP. While there are many benefits to making the switch, there MUST be precautions taken to ensure that your new phone system is safe and secure. more