Ball size: 21/2" (63.57mm)
Interface: Proprietary DB-9
Well-made device for radar operators. According to available sources, the R-POS marking means "Radar position (r-pos) trackball". Device was sold with "Property of FAA" sticker, which confirms that. Calculated resolution is 362 PPR (46 CPI).
As usual for Cortron devices, separate trackball module of classic design is mounted in the desktop enclosure. Inner surface of plastic case have copper coating, apparently to suppress RF interference.
Ball bearings made by NMB (R2 size) are of serviceable type: very handy property, as they were rotating poorly due to dried out factory grease. Common cleaning and re-lubricating procedure fully restored them. Upon assembly, the main bearings are pressed with special rubber inserts. Support bearing have rubber rings attached to its shaft, to prevent side play. After the module is mounted and the ball and debris-protection rings installed, it's covered with separate top cover.
The PCB board seems to be universal for various models: it does have mounting places for button switches and backlight illumination LEDs, but none of them are present in this variant.
Trackball module also have guide channels for button shafts, identical to Cortron 2" model. Obviously, in order to use them, different top cover with embedded buttons would be needed.
Signals from Omron EE-SX1109 sensors are rectified with Texas Instruments SN74HC14 Schmitt trigger. Controller is Cypress CY7C63723C-SXC. As its standard purpose is USB-PS/2 peripheral controller, I was hoping device uses one of these protocols - but unfortunately it's not the case: MCU doesn't respond to them. Totally normal, as Cypress datasheet says "The instruction set has been optimized specifically for USB and PS/2 operations, although the microcontrollers can be used for a variety of other embedded applications", but it means the conversion to pointing device will require MCU replacement.
The button module us surprisingly complicated: it does have its own Microchip PIC16F505 controller, and 3 supplemental ICs made by Texas Instruments: LM293 comparator, SN74HC00 NAND gates, and CD4051BM multiplexer.
Switches are sealed with rubber membrane, serving also as a rubber-dome return springs. Contacts are made with aluminium foil discs attached to the shafts via foam insert. When actuated, foil is pressed against contact zones formed directly on PCB. Similar to the main trackball module, it also have mounting places for illumination LEDs and associated components, but they're not installed in this sample.
Cable with DB-9 screw-on connector:
Device looks almost identical to the Measurement Systems XCL-250, apparently designed for the same purpose, and is significantly larger than Cortron DuraTrack 530-0032 desktop model.
Trackball is quite pleasant to use: after servicing ball bearings, movement is very smooth. Large ball provide nice inertia. Should be really convenient for fine graphics work and similar tasks.
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