Apple Extended Keyboard II

The Apple Extended Keyboard II (AEK II) is the successor to the Apple Extended Keyboard (M0115). Apple describes it as the Extended Keyboard with two additions: a foot to adjust the keyboard's angle and a double-sided template for labelling the function keys. Deskthority gives the production years as 1990-1995 and describes it as the last mechanical keyboard Apple made; it was followed by the rubber-dome AppleDesign Keyboard.

Apple Extended Keyboard II
Apple Extended Keyboard II
Manufacturer	Apple Computer, Inc. (made by Alps Electric and Mitsumi)
Type	Computer keyboard
Release date	1990
Discontinued	1995
Interface	Apple Desktop Bus
Compatible	ADB-equipped Macintosh computers, Apple IIGS
Dimensions	475 × 195 mm; 41 mm high at the rear
Weight	1.8 kg
Predecessor	Apple Extended Keyboard (M0115)
Successor	AppleDesign Keyboard (M2980)
Model	M3501; order no. M0312 (ANSI), M0312Z (ISO)

The US keyboard has 105 keys and the ISO keyboard for Europe 106. Apple's packing lists give M0312 for the US keyboard and M0312Z for the ISO keyboard, each with a 1.0 m ADB cable, the function-key template and an owner's guide. The model number on the label is M3501; Deskthority notes that serial numbers of M0312 keyboards end in "M0312", and that the first letter of the serial number identifies the maker: A for Alps, M for Mitsumi.

Specifications

Apple Extended Keyboard II specifications (Apple)

Item	Value
Keys	105: 60-key alphanumeric block, 18-key numeric keypad, four inverted-T cursor keys, 15 programmable function keys, six editing keys, Escape, Power On/Reset
Size	475 mm W × 195 mm D; 41 mm high at the rear, 19 mm at the front
Weight	1.8 kg
Keyboard angle	6-14°
Home row height	28-34 mm
Key spacing	19 mm
Key travel	3.5 ± 0.3 mm; contact closure at 2.0 ± 0.3 mm
Peak tactile force	0.6 ± 0.1 N at 1.4 ± 0.3 mm
Connectors	two ADB 4-pin mini-circular
Indicators	three LEDs
Power	5 mA with the LEDs off; 18.5 mA with one LED on
Environment	operating 10-40 °C; storage −40 to 47 °C; 95% humidity maximum, non-condensing

The owner's guide gives the cable as 1.9 m (6 ft) with a coiled cord, where the later Tech Info Library packing list gives 1.0 m. The Power On key switches on a Macintosh II and acts as Reset on an Apple IIGS. The Caps Lock LED works under the Mac OS; Num Lock and Scroll Lock light only in applications that use them.

Variants and switches

Deskthority records Alps SKCM Ivory, Alps SKCM Salmon, Alps SKCM White Damped and Mitsumi switches, with the following combinations seen:

• Mitsumi: M0312 keyboards made in Japan (copyright 1989), with Mitsumi PCBs. All Japanese-made keyboards seen have ANSI layouts.
• Salmon: keyboards made in the USA only (M0312, and M3501 with copyright 1989 and 1990).
• Ivory: keyboards made in the USA and in Ireland. The ISO keyboards were built in Ireland.
• White Damped: keyboards made in Mexico (copyright 1995), and in Deskthority's table also Ireland.

Alps SKCM Ivory is the commonest switch. Its slider is a cream off-white, and small rubber inserts on either side of the slider damp both the downstroke and the upstroke, so with its high tactile point the keyboard is sometimes mistaken for a rubber-dome board. Matias later revived the switch as the Matias Quiet. Salmon switches feel similar but have no rubber bumpers and bottom out hard. White Damped is a rare Ivory variant with pure white sliders, not to be confused with the clicky white Alps switches. The Mitsumi switches are all-white Alps-mount sliders, faintly tactile and reportedly quiet.

A label with an "S" inside a square in its bottom right corner indicates damped switches. It has been seen only on M3501s made in the USA or Mexico with Ivory or White Damped switches; Irish-made keyboards with Ivory switches have been seen without it.

Construction

The case is held together by one screw. The single large foot near the back is moved by a slider on the rear, which acts on the foot through an inclined plane. Apple's instructions: with the back of the keyboard facing you, move the slide in the rectangular recess to the right to extend the bar and raise the angle; the slide clicks through its settings and locks where it is released, and the centre of the recess gives about 10°.

Two knobs at the ends of the function row hold the overlay, and the Caps Lock, Scroll Lock and Num Lock LEDs sit above the numeric keypad. The Apple logo is above the Escape key, and the case borders are smaller than the M0115's.

Caps Lock uses a latching switch. The modifier keys and Caps Lock are on dedicated lines; the other keys are in a matrix without diodes. The two Command keys are joined on one line and read as the same key. The switches are mounted in a steel plate whose front tabs interlock with the rubber foot on the underside, so plate and foot hold each other without glue. Each of the two ADB ports, one on each side, is on its own small PCB connected to the main PCB by a ribbon cable; either port can go to the computer.

The keycaps are PBT with dye-sublimated legends in Univers 57 Oblique, except the space bar, which is probably ABS and yellows like the case. The profile is Apple's own, and the function-row keys have vertically oriented stems. On ISO boards the leftmost column of the main block is 0.25 u wider and the rightmost 0.25 u narrower than on ANSI, so the vertical Return key is narrower than on most ISO keyboards.

ADB

Keyboards default to ADB address $02. The AEK II reports the same Device Handler ID, $02, as the Apple Extended Keyboard. For the Extended Keyboard, Apple documents register 0 holding two key events, register 2 holding the modifier keys, Num Lock/Clear, Scroll Lock and the three LED bits (LED 1 Num Lock, LED 2 Caps Lock, LED 3 Scroll Lock; a zero means a key is down or an LED is on), with the LED bits written by a Listen Register 2 command. Changing the Device Handler ID from $0002 to $0003 makes the keyboard send separate codes for the right-hand Option and Control keys; Apple's key-code table also lists a separate right Shift code under the same setting.

All ADB devices together may draw no more than 500 mA, cables should be no longer than 5 m, and Apple does not recommend daisy-chaining more than three devices on one port. The owner's guide gives the ADB port pinout (1 data, 2 power on, 3 +5 V, 4 ground) and the same 5 m cable limit.

Maintenance and repair

Opening the case

Remove the single case screw. The steel plate and the rubber foot interlock, so lift them out together.

Works in one ADB port but not the other

Each port is on its own board on a ribbon cable. Check and reseat both ribbon connectors.

Lock LEDs do not light

Num Lock and Scroll Lock light only when an application drives them, and the LED bits are written by the host. Test with software that uses them before replacing an LED.

Chattering or dead key

1. Remove the keycap, flush the switch with isopropyl alcohol while working it, and let it dry fully.
2. If that fails, desolder the switch and replace it with one of the same type from a donor; the Ivory, Salmon, White Damped and Mitsumi switches feel different.

Things that are not faults

• Left and right Command cannot be told apart: they are one line.
• An Ivory-switch keyboard that feels like rubber domes: the switches are damped.
• No damper symbol on an Irish-built keyboard.

Modern use

Deskthority lists two open-source replacement controller PCBs for the ANSI keyboard: one for an ATmega32A with through-hole parts, and one with a surface-mount ATmega32U4 that adds indicator LEDs and Cherry MX support. An external ADB-to-USB converter keeps the keyboard original; see Apple Desktop Bus.

See also

• Apple Extended Keyboard
• AppleDesign Keyboard
• Apple Adjustable Keyboard
• Apple Desktop Bus
• Retrobrite
• Apple Extended Keyboard II Owner's Guide