Introduction
To enable consistent processing, ClearIP requires all telephone numbers to be in a standard format. The standard format used is E164 format without the leading + or access codes sometimes required for international dialing. Essentially, this format starts with the country code.
Any number translation rules configured within ClearIP only affect ClearIP internal processing. Number translation modifications are removed before ClearIP returns the SIP response to the SBC.
Setup
Number translation rules can be configured to normalize calling and called numbers without modifying existing network hardware. There are two important fields needed to configure a number translation rule:
- Matching Prefix — The prefix used to identify the best matching record. Once the best marching record is selected, the telephone number is split into two parts: the prefix and the remaining part r.
- Rule — The rule to apply to the telephone number. The rule is defined by specifying the desired number. The letter r can be used in the rule to signify the remaining part of the number after the prefix is removed.
Example rules
| Matching Prefix | Rule | Comment |
|---|---|---|
| + | r | Remove the + from all numbers starting with a + |
| 011 | r | Remove the 011 from all numbers starting with a 011 |
| 1r | Add a leading 1 to all numbers | |
| 2 | 12r | Add a leading 1 to all numbers starting with a 2 |
| r1 | Add a trailing 1 to all numbers | |
| 1 | 1r | Do not modify numbers starting with a 1 |
Here is an example Calling Number Translation rule to strip the leading + from the calling number if the SBC sends the phone number in E164 including the leading +. 
Here are example Called Number Translation rules to strip the leading + from the called number if the SBC sends the phone number in E164 including the leading + or to strip the 011 if the called number contains this international dial code. 
Here are example Calling Number Translation rules to add a leading 1 to the calling numbers if the SBC sends the phone number in a 10 digit format without the country code. A leading 1 is added for all calling numbers that do not begin with a 1 already. 