The MD93 series, is a digital clock / chronometer with a Dedicated Charging
Port (DCP) for USB devices (specifically 2 USB charging ports) fitting into a standard 2 ¼” avionics panel cutout. Power is drawn from the aircraft main bus to light a white, six digit, and seven segment LED clock. The clock can display several different modes: local time, universal time, flight timer, elapsed and countdown timer functions. The MD93 LEDs are daylight readable and can be dimmed during reduced light conditions by external voltage stimulus. When the external voltage is not present the clock LED and annunciations are dimmed by means of an internal photocell. The MD93 clock has an internal battery to maintain clock and flight timer functions when the aircraft is not in use.
The Dual USB Charging Port is designed as a DCP (Dedicated Charging Port) to industry-standard protocol per the USB Battery Charging 1.2 Compliance Plan. Early-generation or smaller consumer electronics typically accept one (1.0) amp during charging. However, newer electronics, such as tablets and larger devices can accept, and in some cases, require up to 3 amps to charge and operate. As a high power DCP, the MD93 can provide up to 2.1 amps (p/n 6420043-1) or 3 amps (p/n 6420043-2) to charge any USB device, including the higher demand products. Unlike most dual USB chargers which provide one (1.0) amp on one port and 2.1 amps on the second port, the MD93 can provide 2.1 amps (on -1 unit) or 3 amps (on -2 unit) to both ports simultaneously. With features like short circuit protection, over-current protection, low voltage shut-down and temperature monitoring, it can handle abnormal conditions safely.
Appears to be well made, and presents a very clean, high contrast, white LED display. I chose this clock since it shows seconds, and is also able to show local and UTC/GMT time (with an annunciator with which mode it is in). I prefer 24 hour display, though this unit can also display in 12 hour format if desired. The dual 3A USB outputs will be used with an iPad Pro and/or iPad mini - so this should keep up with the power drain when using ForeFlight. There are 4 wires to connect up - power, ground, dimming, engine timer. It can be just connected up with 2 wires - power and ground. Refer to the instructions for the engine timer connections (as in simply connect to ground to count up whenever the unit is powered, or connect to a switched ground output for engine/flight time). Albeit a bit expensive, its a great addition to the instrument panel.
Yes, this works on 10-32 VDC.
That pin is for the flight timer. If you wish to have this feature, you will need it.