Merge pull request #250114 from rcdun/e164_numbers

898854 State E.164 requirement for both SIP and TEL numbers

Author: prmerger-automator[bot]

articles/communications-gateway/interoperability-operator-connect.md

@@ -67,6 +67,8 @@ You can arrange more interworking function as part of your initial network desig
 - Interworking away from inband DTMF tones
 - Placing the unique tenant ID elsewhere in SIP messages to make it easier for your network to consume, for example in `tgrp` parameters
 
+The Microsoft Phone System requires calling (A-) and called (B-)  telephone numbers to be in E.164 format. This requirement applies to both SIP and TEL numbers. We recommend that you configure your network to use the E.164 format for all numbers. If your network can't convert numbers to the E.164 format, contact your onboarding team or raise a support request to discuss your requirements for number conversion.
+
 [!INCLUDE [communications-gateway-multitenant](includes/communications-gateway-multitenant.md)]
 
 ## RTP and SRTP media