There is a trend nowadays for portable radio telephone units to be increasingly lightweight and compact. This in conjunction with the fact that such units are cordless offers not only enhanced mobility but also true portability, so that the user can readily carry a portable radio telephone unit, for example in a pocket or briefcase, wherever he or she goes. Particularly in the case of cellular radio, this gives the user a very flexible and powerful means of communication, which can always be to hand.
When an incoming call is received by the telephone a call indicator is activated to alert the user to the fact that there is an incoming call. The call indicator may include an audible signal, e.g. a ring tone, and/or a visual signal, e.g. a message such as "CALL" may be flashed on a visual display panel. The call can be answered by the user depressing one of the keys on the telephone keypad which produces the so-called "off-hook" condition in the telephone.
A drawback with cellular telephone systems is that the system allows only a relatively short window of time before an incoming call is timed out, i.e. the incoming call is terminated by the system if the call is not answered within the pre-set time period. In practice this window of time may be as short as only 3-5 rings. This can be very frustrating for a user who intends to take an incoming call, but finds that he is unable to do so only because the telephone may be in a slightly inaccessible place. For example, when driving, the driver may have placed the telephone in an inside pocket of his jacket which he has hung up in the rear of the car. Alternatively for example, the driver may have put the telephone in a briefcase on the rear seat of the car. In either case, if the telephone rings while the subscriber is driving it may be very difficult to stop the car in a safe location, retrieve the telephone, and press a key to answer the call, within the short time allowed. Consequently the call will often be terminated by the system before the subscriber has had sufficient opportunity to take the call, although the intention was to answer it. Clearly this can be frustrating for both the caller and for the subscriber.
EP-A-0381214 discloses a telephone in which a touch sensitive portion is provided, for example, on an external surface of the telephone itself or at some other remote, but accessible, location. The user can answer the call simply by touching the sensor. However, it is necessary not only for the telephone to be accessible, but also for the user to be able to touch the exact location of the sensor, which would not be possible if the telephone were to be in a pocket or briefcase.