TECHNOLOGY HUB

Telephony:

PSTN

PSTN (public switched telephone network), also known as POTS (Plain ordinary telephone service) is the world’s collection of interconnected voice-oriented public telephone networks. It’s the aggregation of circuit-switching telephone networks that has evolved from the start of the first telephone. Today, it is almost entirely digital in technology but follows the principle of providing a connected circuit for a voice call

DDI

DDI stands for Direct Dial In. It is a telephone number that allows a direct dial in to a specific entity with in a Business that could be a person or a fax machine

Integrated Services Digital Network (ISDN)

Integrated services refers to ISDN’s ability to deliver at minimum two simultaneous connections, in any combination of data, voice, video, and fax, over a single line. The entry level interface to ISDN is the Basic Rate Interface (BRI) (referred to as ISDN2), a 128 Kbit/s service delivered over a pair of standard telephone copper wires. The other ISDN access available is the Primary Rate Interface (PRI), which is carried over an E1 (2048 Kbit/s) link in most parts of the world. E1 is 30 ‘Bearer’ channels of 64 Kbit/s (referred to as ISDN30); one ‘Data’ channel of 64 Kbit/s and a timing and alarm channel of 64 Kbit/s.

Voip:

VoIP (voice over IP) is an IP telephony term for a set of facilities used to manage the delivery of voice information over the Internet. VoIP involves sending voice information in digital form in discrete packets rather than by using the traditional circuit-committed protocols of the public switched telephone network (PSTN). A major advantage of VoIP and Internet telephony is that it avoids the tolls charged by ordinary telephone service.

Hosted System

An increasingly popular way to implement a telephone system for an office or group of offices, is instead of buying one or more PBX systems and installing them in the office, to subscribe to a “hosted” service where the PBX system still exists but is owned and run by the service provider and runs on big computers in their hosting centre. The client just owns the IP phone, which register with the PBX over the internet in a secure manner. All the typical PBX functions are available but at a fraction of the cost.
The standard interface for hosted solution is SIP (Session Initiation Protocol)

SIP

The Session Initiation Protocol (SIP) is a communications protocol for signalling and controlling multimedia communication sessions. The most common applications of SIP are in Internet telephony for voice and video calls, as well as instant messaging, over Internet Protocol (IP) networks.

SIP Trunk.

A SIP Trunk is the “voip” equivalent of one or more traditional or ISDN digital phone lines plugged in to the back of your PBX. A SIP Trunk connects your PBX to the ITSP’s gateway server and allows you to make and receive calls from/to your PBX and its extensions via VOIP rather than over traditional PSTN/ISDN lines.

Computer Telephony Integration (CTI)

Computer Telephony Integration – is a blanket term for software which runs on the user’s PC, and communicates with the user’s phone. In its simplest form, this just means that the PC adds to the phone features like you would expect to find on a mobile phone, list of recent phone calls, list of missed phone calls, etc., and perhaps a basic directory system. Calls can usually be initiated by clicking on the number on-screen then picking up the handset. More comprehensive CTI systems integrate with existing directory tools (e.g. Outlook) or with CRM tools (e.g. salesman.com, Act, Goldmine) so that as soon as the phone rings, the screen displays the customer’s information page, can list outstanding queries or bring up recent orders, etc.

Attendant (Auto Attendant)

An automatic response system, such as a voice presenting options such as press 2 for sales, 5 for Lisa, etc., which handles incoming calls and sends them to the appropriate phone or message. Also know as Interactive Voice Response (IVR).

Jitter

As data load increases and decreases, routers on the Internet can create slightly different times that individual packets take to travel from one point to another point. This variation in time is known as jitter.

Latency

The time it takes for a packet to reach its destination. Higher delay times can be an issue, especially for VoIP, where voice delay can be recognized with latency higher than 150 milliseconds. Higher than 500 milliseconds and the conversation is going to be very problematic.

Mean Opinion Score (MOS)

Mean Opinion Score (MOS) provides a numerical indication of the perceived quality of voice transmission after compression and/or transmission and is expressed as a number in the range 1 to 5, where 1 is lowest perceived audio quality and 5 is the highest perceived audio quality measurement. A score of less than 3.5 will

RJ-11

The typical four or 6 wire connector used to connect standard telephone equipment.

RJ-45

An 8 wire connector used to connect Ethernet connections in computers, routers and other Internet devices. This connector is slightly larger than a (RJ-11) telephone connector. IP phone will all have RJ-45 connection

Voice Codecs:

Way to reduce the bandwidth required for a call over an IP connection.
G711 standard is a non-compression codec
G729 uses compression
G722 is compressed but is a wide band codec resulting in better audio

RTP

Real Time Transport Protocol – An Internet protocol that functions for end-to-end network connections for applications that use audio or video.+