A recent move to using VOIP for my home telephone has meant that I need to set up my analogue telephone adaptor (ATA) for use in the UK. There is just a small choice for reasonably priced ATAs and I decided to go for the Cisco SPA112 mainly due its IPv6 capability. However when I installed it I soon discovered that it is IPv4 only despite what Cisco say on their web-site … but that’s another story.

One of the problems with the ATAs is that they all seem to come set up for the telephone service in the USA. There is, however, information on-line on how to set it up for the UK. One thing that’s not too well explained though is how to set up the dialplan for the UK. There are other sites doing this but none are particularly good.

Luckily Wikipedia has a good article on the format of UK telephone numbers and using this I was able to come up with a good dialplan.

Here is my dialplan:

`(08xxxxxxx. | 0[15]xxxxxxxxx. | 0[2379]xxxxxxxxxS0 |14108xxxxxxx. | 1410[15]xxxxxxxxx. | 1410[2379]xxxxxxxxxS0 | 147008xxxxxxx. | 14700[15]xxxxxxxxx. | 14700[2379]xxxxxxxxxS0 | [2-8]xxxxx. |`

<911:999> | <112:999> | 1[0-5][0-5]S3 | 166S3 | [2-8]xxS3 | 999S0 |

1[45]7[1-9]S0 | 116xxxS0 | 118xxxS0 |

00[1-9]x. | 14100[1-9]x. | 147000[1-9]x.)

And here’s the breakdown:

**08xxxxxxx. | 0[15]xxxxxxxxx. | 0[2379]xxxxxxxxxS0**

These are normal UK land-line and mobile numbers. According to wikipedia, numbers beginning with 08 can be 7, 9 or 10 digits long (not counting the initial 0), numbers beginning with 01 or 05 can be 9 or 10 digits long and numbers beginning with 02, 03, 07 and 09 are only 10 digits long. For this last case the number is dialled immediately (the S0 at the end).

**14108xxxxxxx. | 1410[15]xxxxxxxxx. | 1410[2379]xxxxxxxxxS0**

Exactly the same as above but allows the numbers to be prefixed with 141 which withholds your number.

**147008xxxxxxx. | 14700[15]xxxxxxxxx. | 14700[2379]xxxxxxxxxS0**

Again, these are the same as the first set of numbers but allow the numbers to be prefixed with 1410 which releases your number if it is normally withheld.

**[2-8]xxxxx.**

This allows local calls to be made. Note that my VOIP provider automatically adds my local code. If yours does not then it should look like this: “<:nnnnn>[2-8]xxxxx.” (without the quotes) which will add the nnnnn to the beginning of the dialled number. Obviously you need to set your local code in place of nnnnn.

**<911:999> | <112:999>**

For foreign visitors, these will convert 911 and 112 to 999.

**1[0-5][0-5]S3 | 166S3 | [2-8]xxS3 | 999S0**

All the three-digit numbers that could be dialled in the UK including 999.

**1[45]7[1-9]S0**

Four digit numbers such as 1471 and 1571.

**116xxxS0 | 118xxxS0**

Calls to helpline numbers such as 116 006 or directory enquiries such as 118 118.

**00[1-9]x. | 14100[1-9]x. | 147000[1-9]x.**

Dialling international numbers, again like the UK national numbers, 141 and 1470 can be used as prefixes as required.

There is a final set of numbers you may like to add and that is any special codes your VOIP supplier might use. In my case my supplier is Andrews & Arnold and I have these codes (not shown above):

`*[1456]xxx. | *17070S0`