C A I R O

HANDY HINTS

The Desk-Top Console

The Desk-Top Console incorporates the main facilities of the "Palm-Springs" and "Bus-Speaker" accessories in a single item. Its principal application is for the operator who undertakes a lengthy but not too arduous duty in a solo capacitiy. In use, it will resemble an "intercom" or "paging-caller" facility.

Somewhat like the Palm-Springs unit, it has a Gooseneck Microphone and built-in loudspeaker. However the microphone is detachable from a recepticle socket (for easy stowage and alternative mike selection) and the loudspeaker is larger and upward facing for greater sound clarity. The latter is further supplemented by the volume and listen-loud controls of the Bus-Speaker. The lay-out (as described here) has been optimised for the right-handed operator so that s/he may operate and make adjustments with the left hand, while writing messages with the right-hand. But, being a largely personal accessory, the left-handed Constructor may wish to build a mirror-image version.

The item is based on a general-purpose blank console case with a part-sloping front panel (e.g. RS [508-201]). Behind the sloping portion of the front-panel, a 90mm diameter circular loudspeaker is mounted with an appropriate array (or 'artistic' design) of accoustic cut-out holes. (The "HOIME" exhibit has 5 x 'DIN-punch' holes.) Grill-cloth between the speaker and the panel cut-outs, completes the finished appearance.

The flat-top portion of the (cream-coloured) panel houses ALL the additional controls while the front, vertical portion of the panel has a DIN-7 socket (centered in the right-hand half). This outlet permits headphones to be used, when required. The rear, vertical portion of the panel has a Loose-Tail, in-feed chassis plug (centered in the left half, as viewed from the front) and an Auxiliary DIN-7 outlet socket (centered in the right half, as viewed from the front). This latter outlet socket is wired, pin for pin, to the incoming tail signals to support the 'bus' convention. (The (black) case frame has NO items.)

The flat-top portion of the inset panel has six items; arranged in two rows of three items each.

At the centre of the rear row, a DIN-7 socket is provided as the recepticle for a Gooseneck (electret) microphone. (A hard-wired Gooseneck could be considered, but this would make the item very awkward for storage and carrying purposes.) To its left, in the rear left-hand 'third' of the panel, a 100 ohms cermet potentiometer with a "big" knob gives incremental adjustment to the speaker's accoustic output. In front of this, a small biased-toggle switch provides the listen-loud feature. Alongside it and in front of the mike socket, a red-knob push-button switch is wired as the integral PTT control.

To the right of the mike socket, a miniature cermet (100R, 1W) potentiometer is provided as the pre-set adjustment for the audio supplied to headphones plugged-in to the front-panel headphone socket. In front of it, and to the right of the PTT button, a miniature switch provides single-ear muting by making or breaking continuity to the secondary (pin-6) connection of the headphone socket. It is unnecessary to provide two headphone sockets (as in the Single- or Dual-Operator Boxes) because the Operator only requires binaural headphones (if at all) and these are largely unhanded items. However, it is plausible to use this item with a headset, plugged in to the front-panel vertical socket, provided that the Gooseneck mike is removed from its recepticle socket.

All internal wiring of the Desk-Top Console may be made after the items have been physically installed and, unless noted otherwise, all the incoming CAIRO signals are connected to their respective pins of all three DIN-7 outlet sockets.

(When constructing a 'stand-alone' module such as this, remove the 'pin-7' pin from the three DIN-7 sockets before installing. The d.c. inter-link provision is unecessary, as noted elsewhere.)

Update:
99/06/15

G 8 C Q H