Emergency cellular radiotelephone and method therefor
First Claim
1. A method of operating an emergency cellular radiotelephone in cooperation with a cellular telecommunication network having A and B cellular systems, said A and B systems each having a plurality of signalling channels assigned thereto, and said method comprising the steps of:
- receiving, at said radiotelephone, signalling channels assigned to said system A;
receiving, at said radiotelephone, signalling channels assigned to said system B;
identifying, at said radiotelephone after said receiving steps, the one of said system A and system B signalling channels which has a signal with the greatest signal strength; and
communicating, in response to said identifying step, between said radiotelephone and the one of said A and B systems which has said identified one of said channels assigned thereto.
0 Assignments
0 Petitions
Accused Products
Abstract
An emergency portable cellular radiotelephone (10) communicates with the one of A and B cellular systems that offers the best signalling. The radiotelephone may be energized from an internal battery (50) or an external power source (62). A single switch (38) is used to instigate emergency communication services. When a signalling channel is available and the switch (38) is activated, the radiotelephone (10) requests the placement of a call to a "911" phone number. Once the call is established, it may not be terminated at the radiotelephone (10), other than by removing power.
99 Citations
22 Claims
-
1. A method of operating an emergency cellular radiotelephone in cooperation with a cellular telecommunication network having A and B cellular systems, said A and B systems each having a plurality of signalling channels assigned thereto, and said method comprising the steps of:
-
receiving, at said radiotelephone, signalling channels assigned to said system A; receiving, at said radiotelephone, signalling channels assigned to said system B; identifying, at said radiotelephone after said receiving steps, the one of said system A and system B signalling channels which has a signal with the greatest signal strength; and communicating, in response to said identifying step, between said radiotelephone and the one of said A and B systems which has said identified one of said channels assigned thereto. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. An emergency cellular radiotelephone configured for cooperative operation with a cellular telecommunication network having A and B cellular systems, said A and B systems each having a plurality of signalling channels assigned therto, said radiotelephone comprising:
-
means for monitoring said system A signalling channels and said system B signalling channels; means, coupled to said monitoring means, for identifying the one of said system A and system B signalling channels which has a signal strength greater than the signal strength for any other of said system A and system B signalling channels when both system A signalling channels and system B signalling channels are received at said radiotelephone; and means, coupled to said identifying means, for establishing a call through the one of said A and B cellular systems which has said identified one of said signalling channels assigned thereto. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
-
-
21. A method of operating a portable emergency cellular radiotelephone in an environment having at least one of A and B cellular systems, said A and B systems each having a plurality of base stations wherein each system A base station broadcasts a signal over a forward portion of a signalling channel associated with said system A and wherein each system B base station broadcasts a signal over a forward portion of a signalling channel associated with said system B, wherein said radiotelephone has a battery, a power switch, and a control switch, and said method comprises the steps of:
-
energizing said portable cellular phone from said battery when said power switch is activated; energizing said portable cellular phone from an external power source regardless of whether said power switch is activated; monitoring signalling channels used by said system A base stations; monitoring signalling channels used by said system B base stations; identifying, after said monitoring steps, the one of said system A and system B signalling channels which has a signal with the greatest signal strength; detecting a manipulation of said control switch; sending a message over a reverse portion of said one of said system A and system B signalling channels requesting completion of a call to a called party in response to said detecting step, said message being encoded to include the digits "911" as an identity for said called party; and conducting a call with said called party, said conducting step being configured to allow call termination only upon de-engerization of said portable cellular phone or upon a termination instigated by said called party. - View Dependent Claims (22)
-
Specification