Telrad IP Telephone System

Successful, reliable communications are vital in today's business world. When an organisation operates from multiple sites this is no less important, but this introduces extra costs. Telrad Connegy provides various voice and data networking solutions to suit most budgets, incorporating private circuits and/or dial-up services. The secret is to get the most benefit at the least possible cost, which is where Telrad Connegy Networking can help - offering Q-Sig, DPNSS and VoIP with Voice Compression, coupled with a flexible numbering plan to maximise use of Kilostream, Megastream, Frame Relay and ISDN.

Voice over IP

VoIP stands for Voice over Internet Protocol and is today's alternative to the traditional circuit switched telecommunications model. Using Voice over IP (VoIP) it is now possible to route your phone calls, fax and voice mail communications through the Internet or Intranet (IP).

Voice over IP is a digital telecommunications format - the analogue voice signal is digitalised into data packets, sent, and then reconverted back into a voice signal at its destination. VoIP uses TCP/IP to travel across either a private network (Intranet) or across the Internet to its destination. The TCP/IP networks are made of IP packets containing a header (to control communication) and a payload to transport data.

With VoIP it is possible to talk to one or more persons at once, and at the same time, you can exchange data with the people you are talking with - sending images, documents, graphs and videos, and all at a fraction of the cost of a conventional telephone call.

DPNSS: Digital Private Network Signalling

DPNSS is a well established, predominantly UK, inter-PBX protocol that provides a high level of feature transparency between Telrad Connegy and other PBX systems, and additional proprietary features on a Telrad-to-Telrad network. It is also a popular method of accessing Virtual Private Network (VPN) applications. Available on level Version 7 software onwards, Telrad Connegy initially supports fourteen major levels of DPNSS, plus six proprietary (Telrad to Telrad only) features. The BTNR references are contained in the table below, and relate to core telephony functions for inter-PBX operation. Additional DPNSS functions (including enhanced proprietary features) are anticipated in future software releases.

Some of the more important networking features include:

Callback When Free - the calling extension rings when the (busy) called extension is free.

CallBack When Available - the calling extension rings when the (ring-no-answer) called extension is next used.

Infinite Loop Avoidance (anti-tromboning) - calls that are transferred back and forth across the network will only use a single channel.

Page Across Network (Telrad-to-Telrad only) Paging announcements can be made through the speakers of keyphones on the remote site(s).
Busy Lamp Field (Telrad-to-Telrad only) Users can see the status of other users on remote sites this includes busy, ringing and do not disturb.
Centralised emaGEN Voicemail Server (Telrad-to-Telrad only) DPNSS users can benefit from the popular emaGEN Voice Processing Application - now available as a centralised resource across a Telrad network. Users on remote systems access and interact with the voicemail in the same way as local users - enjoying popular features such as Message Waiting LED, Call record plus Screen Prompts.

DPNSS		Telrad to Telrad
BTNR 188 Supplementary Service		Paging through Keyphones
General	Section 1	Centralised ImaGEN - Message Waiting LED
Physical Characteristics	Section 2
Data-Link Layer	Section 2	Centralised ImaGEN - Call Forward direct to mailbox
Message Types and Formats	Section 4
Level 3 Signaling	Section 5	Centralised ImaGEN - Message retrieval direct from Mailbox
Simple Telephony Call	Section 6
Call Back When Free	Section 9
Diversion	Section 11	Centralised ImaGEN - Call Record
Three Party	Section 13
Non-Specified Information	Section 15	Centralised ImaGEN - IVM screens on large display keyphone
Service-Independent Strings	Section 16
Call Back When Next Used	Section 31
Call Back Messaging	Section 36	Centralised ImaGEN - Voice Message feature
		Busy Lamp Field for remote users

QSIG

Q-Sig is the standard European protocol for inter-PBX signaling. It is in the same series as Euro-ISDN (sometimes called Q931) and supports basic call setup, transfer etc. There are very few features available across a Q-Sig link, so most UK PBX networks utilise DPNSS. Both protocols operate on the same Telrad Connegy Network card, so when Q-Sig develops further, Telrad Connegy DPNSS clients will have the option to switch protocols without the need for additional hardware.

Frame Relay

Frame Relay is a method of high-speed data transfer without the need for a point-to-point private circuit. Each Frame Relay user site is connected by a local private circuit (Kilostream/Megastream, etc.) into the Frame Relay "Cloud". There are no "per minute" usage costs, just quarterly contract charges.

SVC - Switched Virtual Circuits establish a connection on demand, with a short handshake delay.

PVC - Permanent Virtual Circuits provide a guaranteed permanent link without handshake delay.