Abstract: A cellular radio telephone system comprises a mobile cellular telephone (1) adapted to have a hand portable telephone (2) containing a number assignment module, i.e. a NAM (7), removably connected thereto. The mobile telephone (1) has a microprocessor (4) which can access the information stored in the NAM (7) of the hand portable telephone (2) either directly or via a memory 16 whereby the mobile automatically assumes the telephone number of the hand portable telephone when the two telephones are connected together. Hence a subscriber need only have a single billing account for both telephones. Also, the same mobile telephone may be used as a host at different times by any number of subscribers having their own hand portable telephones. Each subscriber will be able to receive his own calls and the charges for using the system can be levied to the appropriate subscriber's account.

Abstract: A portable cellular telephone capable of recognizing a Calling Line Identification (CLI) signal. The telephone comprises a memory in which can be stored telephone numbers together with an associated operating instruction. For example the instruction may be for the telephone to respond with a "BUSY LINE" signal. When a call is received which includes a CLI signal the memory is searched to find a number corresponding to the CLI. If a match is found the normal operating sequence is interrupted to carry out the associated instruction. Hence the telephone can respond with a "BUSY LINE" signal for calls originating from selected telephone numbers, providing a call screening facility.

Abstract: A cellular radio telephone system comprises a mobile cellular telephone (1) adapted to have a hand portable telephone (2) containing a number assignment module, i.e. a NAM (7), removably connected thereto. The mobile telephone (1) has a microprocessor (4) which can access the information stored in the NAM (7) of the hand portable telephone (2) either directly or via a memory 16 whereby the mobile automatically assumes the telephone number of the hand portable telephone when the two telephones are connected together. Hence a subscriber need only have a single billing account for both telephones. Also, the same mobile telephone may be used as a host at different times by any number of subscribers having their own hand portable telephones. Each subscriber will be able to receive his own calls and the charges for using the system can be levied to the appropriate subscriber's account.