Hi
You can do this in two ways:
1. On H.323 gateway
voice translation-rule 777
rule 1 /8100/ /0912341000/
!
voice translation-profile 777
translate calling 777
!
voice-port 1/0:15
translation-profile ougoing 777
Instead of 1234 use you prefix. In voice translation rule you can use up to 15 records (you can add records for other phones which need translation). "Translation profile outgoing 777" can also be used in dial-peer voice XXX pots configuration (if you need translation only for some destination patterns);
You can test if your translation 777 is working fine using "test voice translation-rule 777 XXXX" where XXXX is your calling number.
2. You can also do that reconfiguring only CCM.
a. create one additional partition for example TRANS;
b. create one additional CSS which will be used by phone 8100. Partition TRANS should be on the first place in this CSS. You should change CSS for extension 8100 from your CSS to this one;
c. create route-patterns for access your PSTN. In configuration of these route-patterns configure calling party transform mask 0912341000. Access to these route-patterns should have only phone for which you require translation;
What type of phones are you using? External Phone number mask is best solution. I know about this number in the upper right corner, but you can configue line text label with correct number (especialy for 7912 phones)...
Regards
Wojtek
