This chapter is from the book
Allowing H.323 to SIP Connections
SIP and H.323 dial peers can be configured on the same gateway, but call routing between the two types of dial peers is disabled by default. To enable this routing, enter voice service configuration mode and issue the command allow-connections from-type to to-type. Options for both the from-type and the to-type are h323 and sip. Example 4-11 shows a router that is configured to allow multiple types of VoIP connections.
Example 4-11. Configuring H.323 to SIP Connections
H323-SIP-GW(config)#voice service voip H323-SIP-GW (conf-voi-serv)# allow-connections h323 to h323 H323-SIP-GW (conf-voi-serv)# allow-connections h323 to sip H323-SIP-GW (conf-voi-serv)# allow-connections sip to h323 H323-SIP-GW (conf-voi-serv)# allow-connections sip to sip