ATM TELEPHONE T.4087 & T.4088
|MINE TELEPHONES AND SIGNALLING APPARATUS
STROWGER AUTOMATIC MONOPHONES
Many telephone users have commented on the inconvenience of the conventional table-type telephones as entailing the use of both hands whilst speaking, or, alternatively, compelling an awkward and sometimes uncomfortable posture when seated and making notes.
For some time past there has in. fact been a steady and persistent demand for an alternative type of telephone, which would only occupy one hand during conversation, leaving the other free for making notes.
Such a requirement involves a return to the older hand microtelephone, in common use prior to the advent of common battery working, and to meet the case an improved design of telephone has been evolved, known as the 'Monophone,' in which the transmitter and receiver are combined in one convenient unit.
This class of telephone is shown below, and embodies new principles, which are reflected in its pleasing appearance and convenience in use. The fixed cradle and switch are of special design, and ensure positive action of the contact springs. The complete assembly constitutes a perfectly balanced instrument of robust construction.
The circuit incorporates the induction coil principle, the connections being such as to reduce side tone and maintain high transmission efficiency. The complete instruments are supplied in two general forms, which depend upon the design of the induction coil. In one type, the induction coil is fixed in the case of the instrument, together with the dial (as in the picture above), or in the bellbox, whereas, in the second type (see below), a specially designed induction coil is integral with the hand combination itself. The latter type may therefore be used with existing bellboxes.
T.4088. Monophone with separate Bellbox.
Last revised: October 06, 2012