Hi, for this kind of operations you really have a lot of possible choices with kamailio. Some examples: 1) operating directly on $ru, since it is a r/w pseudovariable (http://www.kamailio.org/wiki/cookbooks/devel/pseudovariables#ru_-_request_u…) 2) use textops module's susbst_uri function http://www.kamailio.org/docs/modules/devel/modules/textops.html#textops.f.s… 3) use avp_pushto from avpops module (http://www.kamailio.org/docs/modules/devel/modules/avpops.html#avpops.f.avp…) 4) use dialplan module Hope this helps. Regards, Federico On Mon, Oct 5, 2015 at 12:06 PM, Infinicalls Infinicalls &lt;infinicalls(a)gmail.com <mailto:infinicalls@gmail.com>> wrote: Hi, I am able to successfully connect to a PSTN gw from Kamailio. Now, he says I need to prepend a value (eg.123123) before the number(ENUM) and then only terminate the calls. Where do I add this? Can somebody help me? thanks Ganesh Kumar _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org <mailto:sr-users@lists.sip-router.org> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users