| 摘要 |
<p>A method and apparatus are disclosed for a system where a user terminal 11 can communicate with satellites 9A-C, the satellites 9A-C can communicate with earth stations 7A-E which in turn can communicate with the terrestrial telephone system 1. The user terminal can register with one of the earth stations 5C which has an associated mobile satellite switching centre 5C which acts as a gateway into the terrestrial system 1. When attempting to contact the user terminal 11 from the terrestrial system 1 the mobile satellite switching centre 5C of visitor registration, if it cannot make the contact itself, instructs other earth stations 5, 7, in turn, according to different methods of alternative earth station 7 selection, until contact is made, and then routes all voice messages 21 through itself 5C to retain the single and original gateway into the terrestrial system 1. <IMAGE></p> |
