6-1
6 THE SEA 245 FRONT PANEL/CONTROLLER SYSTEM
6.1
GENERAL
The SEA 245 Front Panel/Controller unit is a complete SEABUSS controller and is
designed in such a manner as to permit direct installation on the front of a standard
SEA 245 as well as in remote installations. The SEA 245 will support a SINGLE
remote controller and a SEABUSS compatible Antenna Tuner such as the SEA
1631. The maximum TOTAL length of SEABUSS cable not to exceed 200 feet (60
meters). The stand-alone Controller (SEA 2450) is designed for shipboard
mounting. Keypad and display are backlighted for operator convenience
Figure 6.1 shows the outline dimensions of the SEA 2450 with mounting bracket.
For information regarding flush mounting, contact the SEA, Inc. factory.
Interconnection between the Front Panel/Controller and the SEA 245 Mainboard
Assembly (ASY-0245-01) when the Controller is directly attached to the
radiotelephone is through an 8-pin DIP connector which carries the standard
SEABUSS interface connections (See Front Panel/Controller (ASY-0245-03)
schematic diagram). This connector (P1) connects to connector J3 on the
Mainboard Assembly (ASY-0235-01) through a short, 8 conductor ribbon cable.
Remotely located Controllers use the standard 9-pin Phoenix style SEABUSS
connector and interconnection is, as stated above, through standard SEABUSS cable
(CAB-2350-XX). The recommended cable is designed to provide adequate
interconnection for the +12VSW line and the PTT line, as well as providing two
shielded, twisted pairs to support the SEABUSS audio circuit and the SEABUSS
data circuit. Note that all SEABUSS cable interconnections are pin-for-pin and that
the shielded twisted pairs are used for audio and data interconnection. See Figures
4.5 and 4.6 for details regarding system interconnections.
6.2
THEORY OF OPERATION
Figure 6.2 shows a block diagram of the Front Panel/Controller Assembly.
The controller(s) are essentially "dumb terminals" configured specifically as the
front panel of a Single Sideband Transceiver. Radiotelephone functions are
controlled by the keypad, transceiver parameters are indicated by the liquid crystal
display (LCD), microphone audio is processed by the circuitry on the Front
Panel/Controller PC board and then routed to the transceiver circuitry through the
SEABUSS audio interconnection, and receiver audio is received from the
transceiver through the SEABUSS audio interconnection and then processed
through the volume control, squelch gate and loudspeaker amplifier to the
loudspeaker.
The controller circuitry is contained on the Front Panel/Controller PC assembly
(ASY-0245-03). This printed circuit board contains the keyboard interface,
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