| 摘要 |
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.
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