ISDN2 or ISDN2e to be exact is the UK’s most popular type of telephone line for voice in the UK for businesses requiring between 2 and 8 lines.


If you want to understand ISDN2e then this web site is exactly what you need – after visiting this site you will have everything you need in order to make an informed decision about ISDN2e.


This site gives you information on:

1.ISDN2e pricing – ISDN2e costs
2.ISDN2e features
3.ISDN2e advice versus ISDN30
4.What ISDN2e line boxes look like
5.How to order ISDN2e
6.What the limitations and disadvantages of ISDN2e are
7.What are the benefits and advantages of ISDN2e
8.How to find a competitive and reliable ISDN2e supplier that can manage the whole process


If your business needs between 2 and 8 voice lines, then ISDN2e is what you need, Note, if you need 8 lines or more, ISDN30 is a better option. Please see ISDN30 for more detail.


ISDN2e can be installed by BT or any other reseller of network services. ISDN2e is installed in pairs of channels. As this is a digital connection each line is referred to as a ‘channel’ rather than a line. Indeed an ISDN2e line refers to a pair of channels. An ISDN2e line (2 channels) is also sometimes referred to as an ISDN2e circuit. Confusing isn’t it?!?


Each ISDN2e line (circuit) therefore provides 2 speech channels. If your business or organisation requires 4 simultaneous speech paths, you will need two ISDN2e lines/circuits providing four channels. If you need 6 simultaneous speech paths, you will need three ISDN2e lines/circuits providing 6 channels and so on.


ISDN2e – Typical features


The most popular and useful ISDN2e features used by most businesses are as follows:


  1. Caller ID – this will provide you with the incoming caller’s number (as long as the caller is not witholding their number). Note if your telephone system has speed dials programmed, it will probably tag the name with the incoming number (not all telephone systems do this automatically!). Caller ID is normally referred to as CLIP which is what you need to order with your ISDN2e connection. Note if you are using a voicemail with your telephone system you will also need COLP which is basically ‘Caller ID for voicemails’.
  2. ‘DDI’s – This stands for ‘Direct Dial Inwards’. This allows your business to allocate different published numbers for different handset users, different groups, departments and so on. You can also allocate DDI numbers for marketing purposes. For example you may decide to publish a specific DDI number on Yell so that you can tell a caller is calling from Yell’s web site – the options here can obviously be expanded to suit you. You can also get clever and allocate DDI numbers to your best customers so that you always know it is them calling you from wherever they are in the world! DDI’s are available as single numbers or in ranges of multiples of 10 – there is a maximum of 5 single numbers, ranges or a combination of both.
  3. Call diversion – this can be set up in advance to divert all calls. Normally calls are set up to divert all calls on no answer after 15 seconds.


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