Problem finding telephonenumber in a plain numeric search when number is stored with special characters

["Walter Kempel" <Walter.Kempel@bs.ch>]

Hello everybody.

I am currently experiencing a problem to satisfy a user request that wants to run a telephony-system enquiry
against openldap

Users would like to see telephonenumbers in the Ldap-directory with the format:  +41(61)26-71234

The telephonysystem would do a search with the filter 41612671234 or the last 5 digits: i.e. 71234

I have tested various index variants in slapd.conf and have not found any way of reaching my goal.

I have no way of influencing the telephony-system.
The people from the telephony told me that they know the system working against a ldap-directory which is based on Lotus Notes. I tested it and indeed found it working.
Teleponenumber:+41(61)26-71234

Searchfilter "(telephonenumber=+41(61)26-71234)" gave correct result
Searchfilter "(telephonenumber=41612671234)" gave correct result
Searchfilter "(telephonenumber=41(61)26-71234)" gave correct result
Searchfilter "(telephonenumber=+41(61)2671234)" gave correct result

It seems that Notes keeps all non-digit characters out of the telephonenumber index AND the search.

How can I achieve the same under OpenLdap?

Regards
Walter Kempel