See typical T69-20A installation photograph beneath. The -SP2 modification contains the -SP1 modification, but additionally permits trunk mounting of P-69-18 by including a cable connector box (see photo under) 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 tips on how to wire the squelch to also be controlled by the distant head, the manufacturing facility squelch management on the chassis then being unused. Squelch was adjusted on the receiver chassis itself and never accessible by the operator. Somewhat frequent. The squelch management was moved to the entrance panel and supplied with a knob, not like previous variations, the place it was located behind a plug button on the side of the housing, as shown on the P-69-thirteen above. The original microphone used with the above control head would have had a straight cord, and would have had a extra flush-showing, "push up to speak" button which recognized the earliest Shure Mfg.

The Motorola P-374-A management head physical appearance is unknown; it's much like different Cruiser heads but has a squelch on/off swap and mechanical volume management knob. The pinnacle for the P-69-17A added a toggle switch for squelch between the pilot lamp and the volume control. The relay within the higher right nook has been added by someone for purposes unknown, probably a receiver muting relay for use with a transmitter. The sq. box on the upper left nook is a transmit-receive 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 isn't an undramatic scene to obtain in the darkened room, when the wet, slippery tape worms out of its case into the palms of the operator. The tape comes prepared with a central line of small holes, insulated copper cable the sprint or the dot being punched on its respective aspect of this line. The -SP1 modification used a small spherical connector on a brief pigtail lead to electrically remote the volume and squelch controls.

As originally configured, the facility provide was often installed on the firewall of the vehicle, next to the receiver and underneath the glove field, while the RF part was located within the trunk and attached to its antenna by way of a brief braided copper rope. The one during which the conducting and nonconducting segments alternate at quick intervals signify the dots, while the opposite two wheels with fewer and longer conducting strips send out the dashes. No sooner does the customer get a glimmering comprehension of those details than he is put up against a machine that ought to scare a married man out of his wits. On examination the machine appears much less formidable. Instead of ready for the wires to clear, the operator sits in entrance of a punching machine feeding from a roll of tape. He ought to be able to perforate the tape at a velocity much in excess of the velocity of telegraphing by hand.

Otherwise, the set is the same as the standard P-69-18. Typically supplied by 1942 was the standard below-sprint P-254 head as also shown beneath, which was usually used with a microphone. This was the standard control head for the T-69-20A although there were at the very least two different styles which were earlier, such as the one shown within the photograph above, which has the connector on the underside apron, and one other, upon which the cradle for a Western Electric "E" style handset was hung. The T-69-20A was introduced in August, 1939. Production continued by way of approximately late 1949. The control head was available as a "handset" type, wherein a push to speak Western Electric "E" series phone handset hung alongside or on a cradle on high of the management head, which was a grey sq. field with Amphenol connectors on the underside for the management cable connections. The management head only controlled the transmitter; the receiver retained its personal control head . This control head was primarily used with the "Deluxe" line of FM equipment, launched in late 1940. Also observe that coiled microphone cords are a postwar development. For example, they have been used within the trunks of Signal Corps staff cars 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 within the late 1940's by surplus sellers offered these as having come from "army police service." There were a number of styles of steel platforms used to mount these "one piece" units.