Communication devices of the present are capable of as many functions as communications devices from science fiction of the past. As communication moves from desk or wall telephones to cellular phones, voice paging and personal communication systems (better known as PCS), the shrinking size of communications devices coupled with the increase in functionality requires very small, multi-functional controls. As a result, there may be confusion as to how to operate these devices.
One area of confusion is signaling; specifically, how to set up a call and how to send further signaling tones through the network once the call is set up. Users are used to one paradigm for a dual-tone, multi-frequency (DTMF) or A touch-tones signaling (referred to herein as DTMF mode or DTMF signaling). Most anyone can use a DTMF keypad to generate signaling that performs tasks as diverse as dialing a telephone number to registering for classes and banking. DTMF signaling presumes that a pair of tones is generated for each key or button pushed and, once the key is pushed, the signal it represents cannot be changed. Call routing menu systems are examples of systems that expect one button, immediate generation of DTMF signaling in this paradigm.
Wireless telephones (also called cell phones, mobile stations and mobile telephones) use a different signaling paradigm. In this paradigm, the user enters digits, which are usually displayed on a screen, and then the user presses a "send" or "enter" key to send the digits into the network as a message. Commonly, there is a "backspace" or "erase" key that permits the user to change one or more entered digits, and a "clear" key to remove all entered digits before the signaling message is sent. This form of signaling will be referred to herein as "dialed digit" or "DD" mode. Once the signaling message is sent, some wireless telephones then cue to a DTMF mode, wherein the user may send DTMF signals through the telecommunication network to perform tasks such as banking, etc.
In the dual mode telephones that have two paradigms operating at any given time, however, it is not always clear to the user operating the telephone which mode a communication device is in (DTMF or DD), and the user cannot control the mode. Furthermore, there are times in the DTMF mode when it is desirable to be able to correct digits before they are sent into the network (i.e., when entering a string of digits representing a credit card number). Consequently, users of new communication devices can easily be confused by the two different signaling paradigms.