See typical T69-20A set up photograph beneath. The -SP2 modification contains the -SP1 modification, but additionally permits trunk mounting of P-69-18 by including a cable connector field (see photo beneath) which allows the receiver to interchange with a Deluxe Line FMR-13V VHF FM receiver and be appropriate with an FMTR-30D radio accessory set. P-69-18 SP-1 and SP-2: Probably 1941 or later-dated modified P-69-18. Also included within the SP-1 guide is an instruction on how to wire the squelch to even be controlled by the distant head, the manufacturing facility squelch control on the chassis then being unused. Squelch was adjusted at the receiver chassis itself and never accessible by the operator. Somewhat widespread. The squelch management was moved to the front panel and provided with a knob, unlike earlier versions, where it was positioned behind a plug button on the aspect of the housing, as shown on the P-69-13 above. The unique microphone used with the above control head would have had a straight cord, and would have had a more flush-appearing, "push up to speak" button which identified the earliest Shure Mfg.

The Motorola P-374-A control head physical appearance is unknown; it is just like other Cruiser heads but has a squelch on/off swap and mechanical quantity control knob. The top for the P-69-17A added a toggle swap for squelch between the pilot lamp and the quantity management. The relay within the upper right nook has been added by someone for functions unknown, in all probability a receiver muting relay to be used with a transmitter. The sq. box on the higher left nook is a transmit-obtain relay to permit use of a single antenna. Were a catastrophe to wipe out a single station, another at an attainable distance could also be used. It is not an undramatic scene to obtain in the darkened room, when the wet, slippery tape worms out of its case into the hands of the operator. The tape comes ready with a central line of small holes, insulated copper cable the dash or the dot being punched on its respective side of this line. The -SP1 modification used a small spherical connector on a short pigtail result in electrically remote the quantity and squelch controls.

As initially configured, the power supply was normally installed on the firewall of the automobile, subsequent to the receiver and underneath the glove field, while the RF part was located within the trunk and hooked up to its antenna via a short braided copper rope. The one during which the conducting and nonconducting segments alternate at short intervals symbolize the dots, while the opposite two wheels with fewer and longer conducting strips send out the dashes. No sooner does the visitor get a glimmering comprehension of these facts than he is put up in opposition to a machine that should scare a married man out of his wits. On examination the machine appears less formidable. Instead of waiting for the wires to clear, the operator sits in front of a punching machine feeding from a roll of tape. He ought to be capable to perforate the tape at a speed much in excess of the speed of telegraphing by hand.

Otherwise, the set is similar as the standard P-69-18. Typically equipped by 1942 was the usual below-dash P-254 head as additionally shown below, which was usually used with a microphone. This was the usual management head for the T-69-20A although there have been at least two different styles which had been earlier, such as the one shown in the photograph above, which has the connector on the underside apron, and another, upon which the cradle for a Western Electric "E" fashion handset was hung. The T-69-20A was introduced in August, 1939. Production continued by means of roughly late 1949. The control head was obtainable as a "handset" sort, by which a push to speak Western Electric "E" sequence phone handset hung alongside or on a cradle on prime of the management head, which was a gray square box with Amphenol connectors on the bottom for the management cable connections. The management head solely managed the transmitter; the receiver retained its personal management head . This control head was primarily used with the "Deluxe" line of FM tools, introduced in late 1940. Also observe that coiled microphone cords are a postwar improvement. For instance, they had been used within the trunks of Signal Corps staff automobiles for the 1940 annual War Games at Camp McCoy, Sparta, Wisconsin (believed to be P-69-17A / T-69-20A mixtures, (in a TR 20-17 setup.) Advertisements in CQ Magazine in the late 1940's by surplus sellers provided these as having come from "navy police service." There were a number of sorts of steel platforms used to mount these "one piece" sets.