Abstract: A keyboard and attached interface for a conventional call box is disclosed. The interface constitutes an interrupt between the cellular telephone handset and cellular transceiver which is activated either by a conventional keypad "On" switch or in conjunction with the telephone hook switch. The TDD keyboard is contained within the call box behind its own discrete door where interference with conventional voice communication cannot occur. Upon opening of the keyboard door, the keyboard activates an interactive display which scrolls status messages to the user informing him of call status upon activation of the keyboard. Switching from voice to keyboard communication is enabled until the answering dispatch center interrogates the call box for identity and necessarily location. Assuming that keyboard communication is selected, necessary communication delay is accepted until communication with a TDD capable dispatcher is established.