ISDN 30 is mainly used by medium to large size businesses with a telephone system (PABX) on their premises, who require their voice and data services to be received and delivered either singly or integrated together.

Each ISDN 30 service is delivered as a 2 Mbits service. It is provided into your premises from your local BT telephone exchange over either a copper or fibre circuit or via a radio connection. It comprises of 30 independent 64 Kbps channels, plus two further channels - one for synchronisation and maintenance, the other for service signals. When newly provided, a minimum of eight 64 Kbps channels must be operational. Additional channels can be provided as and when required, either singly or in batches. When you reach the position of having 30 channels operative but need more, a new ISDN 30 service can be delivered and linked, providing up to another 30 channels.

Using ISDN 30 enables a wide range of applications to be run at any speed from 64 Kbps up to 2 Mbits, such as :-

File transfer between computers.
Internet Access.
Video conferencing.
Inter office remote network access.

ISDN 30 circuits support DDI "Direct Dialling In" and many Select Services. Most of these, although only if you so choose, can be integrated via your telephone system into your computers' operating system to create a CTI "Computer, Telephony Integration" service for your company.

Herewith a listing of the ISDN 30 Select Services that are currently available.

DDI - Direct Dialling In
DDI numbers allow you to increase the amount of telephone numbers you have available for people to call you. DDI numbers are provided either as single numbers (SNDDI's) or in blocks of ten. To give an example. Your main (switchboard) telephone number would be 020 900 9000 and your 7x 10 number DDI range would be telephone numbers 020 900 9001 to 020 900 9070. Using DDI allows you to allocate individual extensions their own inbound telephone numbers, so people can ring your employees directly, without going via your switchboard.

In the event that a DDI number that has been dialled is either engaged or not answered, the DDI can be set up to automatically route the call to the switchboard or to another extension. Alternatively, by utilising an ISDN Select Service, such as CCCF "Customer Controlled Call Forwarding" the unanswered call can be forwarded to another (fixed line or mobile) phone number, without the caller experiencing any delay.

PNCLI - Presentation Number Calling Line Identity
Presentation Number (PN) allows you to specify a telephone number for your Calling Line Identity (CLI) for outgoing calls, which may be different to your usual telephone number. For example, your company's branches could present your call centre's 0800 number to direct return calls to the call centre, rather than back to the branches, thus resulting in improved customer handling. PN is often used in conjunction with our "Non-Geographic-AREA CALL NUMBER" service.