Bimodal portable telephone

Abstract

A bimodal portable telephone provides cellular service and improved cordless service in a common handset. Operation of the bimodal portable telephone in a cellular telephone system provides telephone service over a wide geographical area of coverage through operation with multiple cellular bases and in a cordless telephone system provides telephone service over a localized geographical area of coverage through operation with an associated cordless base. The cordless service provides improved performance over convention cordless telephone service by advantageously employing a frequency hopping spread spectrum modulation technique for communications between the portable telephone and the cordless base unit. This improved performance achieves increased operating range of the cordless telephone system. This increased operating range is particular advantageous to the user of the portable telephone in that it permits this more economical system to be used over a much greater distance than is possible with convention cordless telephone service. Also commonality of circuitry within the portable telephone is facilitied through the selection of operating frequencies for the cordless telephone system to be in close proximity with those of the cellular telephone system.