INTERNATIONAL TELECOMMUNICATION UNION ITU-T RECOMMENDATION SUMMARY Rec. No. : E.173 Title : Routing plan for interconnection between public land mobile networks and fixed terminal networks Study Group : II - Network operation Version : New Date of adoption : 1991 Notes : With the worldwide introduction of public land mobile service there exists a need for interconnection between public land mobile networks (PLMN) and fixed terminal networks (e.g. PSTN/ISDN and PSPDN). Recommendation E.173 covers the routing plan for interconnection between PLMN and the public switched telephone network/integrated services digital network (PSTN/ISDN) and between PLMN and the public data networks (PDN). It provides guidelines for routing when interconnecting PLMN and fixed terminal networks, and indicates some basic rules for routing of calls between the networks. Routing between networks must adhere to regulatory conditions which exist within a given country or Administration. Bilateral agreements may be required to establish the actual interconnection arrangements between network operators. Recommendation E.173 covers terrestrial-based PLMNs. Satellite-based PLMNs are for further study. To order the complete text of this Recommendation, please use the Order Form for ITU-T Recommendations. An electronic version of this form is available on ITUDOC (Winword: UPI=ITU-5265; ASCII: UPI=ITU-2488).