ATA dial plans - how do they work?

Ok, so on my Cisco SPA112 ATA, I have an entry in the dial plan field that looks like this:

(*xx|[3469]11|0|00|[2-9]xxxxxx|1xxx[2-9]xxxxxxS0|xxxxxxxxxxxx.)

The one on the Granstream does not look quite as complex, but what does this all mean? How does it work? How does one interpret it?

Given that your question is "What does it all mean?", I can't answer directly but I suggest you google "ATA dial plan syntax", which should yield some answers

Adding the keyword 'syntax' was helpful here and found a little more information so thank you for that.
I can see that a pipe '|' separates multiple rules and that something like [2..9]xxxxxx would be a matching operator that would match numbers from 2000000 to 9999999 but am still a little unsure about the data inside the <> brackets but I am presuming its a substitution? So <:11> xxxxxxx would replace the 11 prefix with nothing you it just dials xxxxxxx?

But how does this example work to block a call to area code 555?

<:1> 555 xxxxxxx !

I presume the exclamation mark is relevant in some way?

Anyway this is a good start, so thank you for that.

Also why do some rules need a timer? Why is it sometimes at the begining sometimes at the end?

Edited by TruthDigital (Fri 26-Sep-25 19:52:48)

In reply to a post by TruthDigital:

Ok, so on my Cisco SPA112 ATA, I have an entry in the dial plan field that looks like this:

(*xx|[3469]11|0|00|[2-9]xxxxxx|1xxx[2-9]xxxxxxS0|xxxxxxxxxxxx.)

The one on the Granstream does not look quite as complex, but what does this all mean? How does it work? How does one interpret it?

Search for "cisco spa112 manual"

Something like "(999S0|11[1234579]S0|101S0|1x7[1-9]S0|123S0|16xS0|15[0234568]S0|116xxxS0|118xxxS0|**1571xxxS0|**2xxS0|xxx*xxxS0|3xxxxxxx*xxxS0|1410[1-8]xxxxxxxxxS0|14700[1-8]xxxxxxxxxS0|0[1-8]xxxxxxxxxS0|14100[1-9]x.|147000[1-9]x.|00[1-9]x.|<:01799>[2-9]xxxxxS0|09xxxxxxxx.!|*x.|*x#|*xx|*xx#|*#xx#|**x|*xx*|*xxx#|*#xxx#|#xxx#|#xx#)"

Where 1799 is the area code which can be omitted.

Sorry, no answers. I think you know more about it than I do now!

** I'm not an expert on dialling plans. Suggestions given should be verified. I wouldn't want to suggest a plan that stops a critical number being dialled **

Perhaps make the dial plan as simple as possible? Advantage that if numbers change the plan would still work.

For a HT801 I understand this is the default dial plan { x+ | \+x+ | *x+ | *xx*x+ }

Perhaps it is possible to add something for local dialling (that is dialling without the area code) if it is supported / allowed in your area. For example, Milton Keynes (01908) doesn't support local dialling. If it did, then I *believe* something like

{ <=01908>[2-9]xxxxx | x+ | \+x+ | *x+ | *xx*x+ } would add 01908 to 6 digit number dialled from 222222 - 999999

I am not sure how 999 would be treated with the above - there may be pause while the ATA says "I've got 3 nine's - so are there any more so I can apply the rule? So perhaps need 999S0 need to be before the 01908 rule - which I believe means dial 999 immediately - without delay.

Dial plans can be useful in restricting numbers. For example, ensuring the speaking clock isn't dialled.

I've seen this one quoted in many articles / posts:

{ 10[015] | 11[129] | 999 | 11[68]xxx | 1[45]7[1-2] | 08001111 | 0845464x | 0[1235789]xxxxxxxxx | 1410[1235789]xxxxxxxxx | 14700[1235789]xxxxxxxxx | 00xxx. | x+ | \+x+ | *x+ | *xx*x+ }

{ 10[015] | Operator, Police, Power
11[129] | NHS, Police, Covid
999 | Emergency Service
11[68]xxx | Samaritans and others
1[45]7[1-2] | Network Services e.g. 1571
17070 – BT Line Test
08001111 | NSPCC
0845464x | ??????????????? old NHS direct 0845 4647
0[1235789]xxxxxxxxx |
1410[1235789]xxxxxxxxx | Withhold calling number
14700[1235789]xxxxxxxxx | Show calling number
00xxx. | International
x+ | \+x+ | *x+ | *xx*x+ }

Thank you for your detailed post.

I still don't understand what the default { x+ | \+x+ | *x+ | *xx*x+ } plan is doing, but thank you for explaining in detail the example that you posted.

x+ x represents 0 to 9. The + means the proceeding character x (0-9) can appear one or more times

\+x+ \ tells the ATA to interpret next character literally - for international numbers e.g .+44 and then x+ as above

*x+ ATA accepts * literally and then accept x+ as above. Not sure why anyone would dial * followed by numbers in the UK. Perhaps accessing voicemail services?

*xx*x+ ATA accepts * literally followed by two digits [00-99] followed by x+ as above.
Perhaps some carrier pre select e.g. when calls could be routed by Mercury / Cable and Wireless back in the 1980s?

I would think that in the UK, since traditional landlines use 00 for international access (unlike mobiles with +) then the only rule to allow all calls to be matched by the dial plan is { x+ }

I'm not an expert.

Perhaps save your current dial plan and try calling different numbers?

Thank you.

I did wonder whether *x+ (now that you have confirmed what the + means) might e for a switchboard whare you might dial *9 for an outside line?

*xx*x+ however threw me completely. Not sure why one would dial * then two digits then another * followed by another series of digits. It could be as you suggest, but long since deprecated.

You are correct that international calls would start with 00 so 00x+ or x+ would match.

Anyway, that has helped me understand a lot more. It looks a bit intimidating at first until one sees a few examples explained.

Thanks again.