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Rebuild from Deskthority (M1242 and Alps SKFR/SKFS articles) + Guide to the Macintosh Family Hardware ch.8. SKFS has full 3.5 mm travel (not 2.5) and a UNIQUE keycap mount, not Alps-compatible; weight is 1005 g + 372 g, not 2.1 kg. Deleted three unverifiable magazine reviews with invented issue dates, 50,000-75,000 unit production estimate, market-value table, dimensions, prices, actuation forces, 8x16/6x8 matrix sizes, serial-number format, Singapore/Taiwan manufacturing claim and the OSHA/R...
Add Apple's specifications (TIL 11225/11226, now hosted): key counts, supply and LED current, key travel and force, sizes, Apple weights (1.055/0.405 kg; Deskthority's 1,005/372 g differ), order number and box contents; HSU 2.0 Key Caps note
 
(One intermediate revision by the same user not shown)
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{{Infobox computer peripheral
{{Infobox computer peripheral
| name        = Apple Adjustable Keyboard
| name        = Apple Adjustable Keyboard
| image        = [[File:Apple Adjustable Keyboard.jpg|250px]]
| image        = [[File:Apple Adjustable Keyboard.jpg|260px|frameless]]
| caption      = Apple Adjustable Keyboard M1242 with its separate keypad
| caption      = Apple Adjustable Keyboard M1242 with its separate keypad (wrist rests removed)
| manufacturer = Apple Computer, Inc.
| manufacturer = Apple Computer, Inc.
| type        = Ergonomic split keyboard
| type        = Ergonomic split keyboard
| release date = 1993
| release_date = 1993
| price        = US$219 (announced list price)
| interface    = [[Apple Desktop Bus]]
| interface    = [[Apple Desktop Bus]]
| compatible  = ADB-equipped Macintosh computers
| compatible  = ADB-equipped Macintosh computers, including PowerBooks
| weight      = 1005 g (keyboard), 372 g (keypad)
| weight      = 1.055 kg (keyboard), 0.405 kg (keypad), without palm rests
| model        = M1242
| model        = M1242 (order no. M1242LL/A)
}}
}}
<templatestyles src="Template:StyledTable/styles.css" />
<templatestyles src="Template:StyledTable/styles.css" />
The '''Apple Adjustable Keyboard''' (model M1242) was Apple's only split ergonomic keyboard. It is two halves hinged at the '''centre rear''' that swing apart horizontally, with the '''large space bar remaining in the centre, attached to the fixed base'''.<ref name="dt">"Apple Adjustable Keyboard", [https://deskthority.net/wiki/Apple_Adjustable_Keyboard Deskthority wiki]. Part number M1242; FCC ID BCGM1242; modified ANSI or ISO layouts; Alps SKFS main switches with microswitches for the upper navigation cluster and function keys; PCB mount; ADB interface; weights of '''1005 g for the keyboard and 372 g for the keypad'''; two halves hinged at the centre rear with the large space bar fixed to the centre base; removable wrist rests, one per side plus one for the keypad; and the function keys and navigation cluster being located on the keypad rather than the main unit. Photographic galleries of German QWERTZ and US/Russian JCUKEN examples, boxed contents, both PCBs and the disassembled cases. '''Community wiki, cited as a secondary source''', photograph-backed.</ref> It shipped with removable wrist rests — one per side — and with a '''separate numeric keypad''' that has its own wrist rest and carries '''the function keys and the navigation cluster''', neither of which is on the main unit at all.<ref name="dt" />
The '''Apple Adjustable Keyboard''' (model M1242) is Apple's split ergonomic keyboard for ADB Macintosh computers, introduced in 1993.<ref name="dt">Deskthority wiki, [https://deskthority.net/wiki/Apple_Adjustable_Keyboard "Apple Adjustable Keyboard"]: part number M1242, FCC ID BCGM1242, modified ANSI or ISO layouts, Alps SKFS switches and microswitches, PCB mount, ADB, weights 1,005 g (keyboard) and 372 g (keypad), which differ from Apple's figures; introduced 1993; description of the hinge, space bar, wrist rests and keypad; photographs of both PCBs. Community wiki, secondary source. Retrieved 2026-09-30.</ref> The two halves are hinged at the centre rear and swing apart horizontally, up to 30 degrees, with the 6, Y, H and N keys on the right-hand half. The enlarged space bar stays fixed in the centre.<ref name="dt" /><ref name="tb">Adam Engst, [https://tidbits.com/1993/01/11/apple-adjustable-keyboard/ "Apple Adjustable Keyboard"], ''TidBITS'', 11 January 1993: opening angle up to 30 degrees, split with 6, Y, H and N on the right, fixed enlarged space bar, detachable palm rests, separate extended keypad on a short ADB cable for either side, round keys for Escape, sound and function keys, volume, mute and microphone controls, expected list price US$219, ADB Macs and PowerBooks, sound-key software for System 6.0.7 and later. Retrieved 2026-09-30.</ref> The keyboard came with removable wrist rests, one for each half, and a separate keypad with its own wrist rest.<ref name="dt" />


Deskthority gives the weights as '''1005 g for the keyboard and 372 g for the keypad''' — 1.38 kg for the pair.<ref name="dt" /> The FCC ID is '''BCGM1242''' and the layouts are modified ANSI or ISO.<ref name="dt" />
The keypad holds the function keys, the navigation cluster and the numeric keys, and connects to the keyboard by a short ADB cable. It can sit on either side of the keyboard.<ref name="tb" /> The main keyboard has volume, mute and microphone-record buttons on its right-hand half, the first Macintosh keyboard with sound controls; Apple's software for them needed System 6.0.7 or later. The Escape key, the sound buttons and the function keys are small round keys.<ref name="tb" /> ''TidBITS'' reported an expected list price of US$219.<ref name="tb" /> The FCC ID is BCGM1242 and the layouts are modified ANSI or ISO.<ref name="dt" /> Apple sold it as order number M1242LL/A with the keyboard, the keypad, three palm rests, a keypad template, a 3 ft coiled ADB cable, a 1 ft ADB jumper cable and an installer disk.<ref name="til">Apple Computer, Tech Info Library articles 11226, "Apple Adjustable Keyboard: Description (Discontinued) (5/95)", and 11225, "Apple Adjustable Keyboard: Specifications (Discontinued) (5/95)". Hosted in [[:File:Apple Tech Info Library ADB keyboard and mouse articles.pdf]], PDF pp. 10-14.</ref>
 
== Specifications ==
{| class="wikitable styled-table"
|+'''Apple Adjustable Keyboard specifications (Apple)'''<ref name="til" />
! Item !! Value
|-
| Keys || 111 (ANSI), 112 (ISO): main keyboard 68 (ANSI) or 69 (ISO); keypad 43
|-
| Main keyboard || Escape and power-on keys; volume up, volume down, mute and record keys; green Caps Lock LED; two ADB connectors
|-
| Keypad || 18-key numeric pad, 15 function keys, four inverted-T cursor keys, six editing keys; two ADB connectors
|-
| Supply || 5 V DC ±10%; main keyboard 7 mA with the LED off, 19 mA with it on
|-
| Typing keys || 3.5 mm travel; peak tactile force 0.69 ± 0.25 N at 1.5 mm; minimum life 10 million cycles
|-
| Opening angle || 0-30°
|-
| Slope || 5° with the flip feet closed, 12.5° open
|-
| Main keyboard size || 385.6 mm W × 159 mm D × 37.5 mm H (rear, feet closed)
|-
| Keypad size || 248.3 mm W × 143.7 mm D × 37.5 mm H
|-
| Weight || keyboard 1.055 kg (1.223 kg with palm rests); keypad 0.405 kg (0.481 kg with palm rest); 1.7 kg in all
|-
| Cables || 1.0 m coiled cord and 340 mm cable
|-
| Software || System 6.0.7 or later
|-
| Environment || operating 10-40 °C; storage −40 to 47 °C; 95% humidity maximum, non-condensing
|}


== Switches ==
== Switches ==
=== Main keys ===
The alphanumeric keys use Alps SKFS switches, from the low-profile PCB-mount SKFR/SKFS series.<ref name="dt" /> Although low-profile, the switches have the full 3.5 mm travel. The switch is 10.3 mm tall and has an integrated jumper. Its keycap mount is unique to the series, not the common Alps mount, and it is neither pin- nor keycap-compatible with Alps SKFL, so Alps-mount keycaps do not fit and an SKFL is not a substitute.<ref name="skfs">Deskthority wiki, [https://deskthority.net/wiki/Alps_SKFS "Alps SKFR/SKFS series"], with part numbers from the 1994 Alps catalogue: 3.5 mm travel, 10.3 mm height, integrated jumper, unique keycap mount, not compatible with SKFL; SKFS White (SKFSAA) tactile, with photographs of the switch from an Apple Adjustable Keyboard and of NOS switches. Retrieved 2026-09-30.</ref>


Two mechanisms, and the difference between them is the keyboard's defining characteristic in use.
The variant fitted is SKFS White, Alps model SKFSAA, the tactile member of the series. Its click leaf sits in front of a chamber with an open front wall, so when released the leaf strikes nothing and the switch does not click.<ref name="skfs" /> The 1994 Alps catalogue nonetheless lists SKFS as clicky.<ref name="dt" />
 
=== Main keys: Alps SKFS ===
The alphanumeric keys use '''Alps SKFS''', from the low-profile PCB-mount SKFR/SKFS series.<ref name="dt" /> Two things about these switches are routinely got wrong:
 
* '''They keep full 3.5 mm travel''' despite being low-profile — the switch body is 10.3 mm tall and includes an integrated jumper.<ref name="skfs">"Alps SKFR/SKFS series", [https://deskthority.net/wiki/Alps_SKFS Deskthority wiki], with part numbers taken from the 1994 Alps catalogue. Low-profile PCB-mount switches that retain '''full 3.5 mm travel''' despite their size; '''10.3 mm tall''' with an integrated jumper; '''the keycap mount is unique to the series and is not the common Alps mount''', and the switch is neither pin- nor keycap-compatible with Alps SKFL. SKFS White (model SKFSAA) is the tactile member of the series and is the switch fitted to the Apple Adjustable Keyboard: a click leaf sits in front of a chamber whose front wall is open, so when the leaf is released it has nothing to strike and '''produces no click sound''' — greater tactility than a typical tactile leaf, at the cost of empty space inside the switch. Deskthority notes that US patent US4935591, filed 1988, resembles the design but that no patent has been confirmed for it.</ref> Claims of 2.5 mm or 1.5 mm travel for this keyboard are wrong.
* '''The keycap mount is unique to the series and is not the common Alps mount.'''<ref name="skfs" /> It is also not pin- or keycap-compatible with Alps SKFL. Alps-mount keycaps will not fit, and an SKFL is not a substitute.
 
The variant fitted here is '''SKFS White, Alps model SKFSAA''', the tactile member of the series.<ref name="skfs" /> Its mechanism is genuinely clever: a click leaf sits in front of a chamber whose front wall is open, so when the leaf is released '''it has nothing to strike and makes no click sound'''. The result is more tactility than an ordinary tactile leaf gives, at the cost of empty space inside the switch.<ref name="skfs" />
 
Deskthority's Adjustable Keyboard article describes SKFS as "clicky" on the strength of the 1994 Alps catalogue.<ref name="dt" /> The switch article, which is based on disassembled examples and photographs of the leaf, is specific about why it '''cannot''' click.<ref name="skfs" /> The catalogue wording appears to describe the tactile event rather than an audible click; the mechanical description is the one followed here.
 
=== Function keys and navigation: microswitches ===
The upper navigation cluster and the function keys — all of which live on the separate keypad — '''are not key switches at all'''. They are buttons over what appear to be simple microswitches.<ref name="dt" /> This is the keyboard's most-criticised feature: the function keys feel nothing like the main keys and take noticeably more force. No published actuation figures for them could be found and none are stated here.
 
== ADB Behaviour ==
 
The keyboard and the keypad are '''two separate ADB devices'''. Both default to address '''$02''', the address Apple reserves for encoded devices, which means the bus has to resolve an address collision between them at every startup: the Start Manager sends Talk Register 3 to $02, both answer, one loses the collision, and the winner is moved to a free address with a Listen Register 3 command carrying Handler ID '''$FE'''.<ref name="gmfh">''Guide to the Macintosh Family Hardware'', second edition, Apple Computer, Inc. / Addison-Wesley, 1990 — hosted on this wiki as [[:File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf]]. Chapter 8, "Apple Desktop Bus": Table 8-1 connector signal assignments (470 Ω pull-up, POWER.ON on pin 2); Table 8-2 transceiver electrical characteristics; Table 8-4 register 0 in the Apple Standard Mouse and its note on 100 ±10 / 200 ±10 counts per inch; Tables 8-7 and 8-8 registers 0 and 2 in the Apple Standard Keyboard; Tables 8-10 and 8-11 registers 0 and 2 in the Apple Extended Keyboard and the $0002 → $0003 Device Handler ID change for right-hand Option and Control; Table 8-13 command byte syntax; Table 8-14 the full ADB timing specification; Table 8-15 device register 3; Table 8-16 device addresses; Table 8-17 reserved Device Handler IDs; the 500 mA total bus limit, the 5 m / 100 pF-per-metre cable limits, the 11 ms idle polling interval and the warning against unplugging a device while the computer is running. Chapter 9, "Floppy Disk Interfaces": Table 9-1 drive capacities, file systems and encoding; the IWM and SWIM interface ICs; internal 20-pin and external DB-19 pinouts; drive current requirements; and the PWM motor-speed line used only by 400K single-sided drives.</ref>


That matters practically. '''If the keypad intermittently disappears, suspect collision resolution before suspecting the keypad.''' Apple's specification says devices should assert their start bit at a random time within the stop-to-start window precisely because two devices on nearly identical clocks may fail to detect a collision at all.<ref name="gmfh" /> A marginal ADB cable or a long chain makes this worse.
=== Function keys and navigation cluster ===
The function keys and the upper navigation cluster on the keypad are round buttons over what appear to be simple microswitches.<ref name="dt" /> ''TidBITS'' questioned at launch whether these harder-to-press keys suited an ergonomic keyboard.<ref name="tb" />


Other published figures that apply:<ref name="gmfh" />
== ADB devices ==
* '''Register 0''' carries two key events in one read, so two-key reporting is normal.
The keyboard and the keypad each have two ADB connectors<ref name="til" /> and are separate ADB keyboard devices on the same bus. The keyboard reports Device Handler ID $10 (ANSI), $11 (ISO) or $12 (JIS); the keypad reports $0E.<ref name="tmk">TMK keyboard firmware wiki, [https://github.com/tmk/tmk_keyboard/wiki/Apple-Desktop-Bus "Apple Desktop Bus"], "Keyboard Handler ID" (Apple Adjustable Keypad M1242 0x0E; Apple Adjustable Keyboard M1242 0x10, ISO 0x11, JIS 0x12) and "Apple Adjustable Keyboard Media keys" (volume up, volume down, mute and microphone from appliance address 7). Retrieved 2026-09-30.</ref> Keyboards default to ADB address $02, and when two devices share a default address the Start Manager gives one of them a new address at startup.<ref name="g287">Apple Computer, ''Guide to the Macintosh Family Hardware'', 2nd edition (1990), chapter 8, "Apple Desktop Bus", p. 287. Hosted as [[:File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf]].</ref> The four sound buttons are a third device, at ADB address 7, which the Linux driver lists as the "Adjustable keyboard button device" (original handler ID $02) with microphone, mute, volume-down and volume-up events.<ref name="tmk" /><ref name="linux">Linux kernel, [https://github.com/torvalds/linux/blob/master/drivers/macintosh/adbhid.c drivers/macintosh/adbhid.c], ADB_MISC handler 0x02 "Adjustable keyboard button device". Retrieved 2026-09-30.</ref>
* '''Register 2''' carries modifier-key status, with 0 meaning down.
* Apple documents no polling rate; in the idle state the transceiver repeats the last Talk command '''every 11 ms'''.
* All devices on the bus together must draw no more than '''500 mA''', and Apple recommends no more than '''three devices''' on one ADB port. A keyboard plus a keypad plus a mouse is already at that limit.


== Maintenance and Repair ==
Apple's bus limits apply to the set as a whole: 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 ADB port.<ref name="g292">''Guide to the Macintosh Family Hardware'', 2nd ed., p. 292.</ref> Do not unplug and reconnect an ADB device while the computer is running: the device reverts to its default address while the computer keeps using the address it assigned at startup.<ref name="g287" />


=== Before you open it ===
== Maintenance and repair ==
The two units are separate assemblies with separate PCBs.<ref name="dt" /> Diagnose which one is at fault first — they can be tested independently by plugging each in on its own.
The keyboard and the keypad are separate assemblies with their own PCBs.<ref name="dt" /> Because each is its own ADB device, test them one at a time, each connected directly to the computer, to find which unit is at fault.


=== Wrist rests keep falling off ===
=== Wrist rests ===
The rests are removable by design.<ref name="dt" /> Missing rests are the commonest thing wrong with a surviving set, and a complete set is three of them: two for the keyboard and one for the keypad.<ref name="dt" />
The rests are removable by design. A complete set is three: one for each half of the keyboard and one for the keypad.<ref name="dt" />


=== Dead or chattering main key ===
=== Dead or chattering main key ===
# Remove the keycap carefully — the SKFS mount is unique and fragile, and a broken stem cannot be replaced from any other switch family.<ref name="skfs" />
# Remove the keycap carefully. The SKFS keycap mount is unique to the series, so a broken keycap or stem cannot be replaced from another Alps family.<ref name="skfs" />
# Flood the switch with 90%+ isopropyl alcohol, actuate repeatedly, dry fully.
# Clean the switch with isopropyl alcohol, actuate it repeatedly and let it dry fully.
# If that fails, the switch must come out. '''There is no drop-in substitute''': SKFS is PCB-mount, has a unique keycap mount and is not compatible with SKFL.<ref name="skfs" /> A donor Adjustable Keyboard is the only realistic source. NOS SKFS switches do surface from surplus sellers.<ref name="skfs" />
# If that fails, the switch must be desoldered and replaced with another SKFS. Donor Adjustable Keyboards are the usual source; new-old-stock SKFS switches have been sold through online surplus sellers.<ref name="skfs" />
 
=== Dead function key ===
Those are microswitches under button caps, not key switches.<ref name="dt" /> Clean them with contact cleaner and work them repeatedly; a generic microswitch of the same footprint is a more plausible substitute here than anywhere else on the keyboard.
 
=== Keypad not recognised ===
# Try the keypad alone, connected directly to the computer with nothing else on the bus. If it works alone but not with the keyboard, the problem is address-collision resolution, not the keypad.<ref name="gmfh" />
# Shorten the chain and replace suspect cables before anything else.
 
=== Split angle will not hold ===
The hinge is at the centre rear and the halves swing out horizontally.<ref name="dt" /> Friction is what holds them. Do not lubricate it — that removes the only thing keeping the position.
 
== What Is Not Documented ==
 
Apple published a great deal less about this keyboard than the collector literature implies. No dimensions, retail price, production figures, sales data, manufacturing locations, serial-number format or actuation-force figures for either mechanism could be traced to Apple or to a photograph-backed source, and none are stated here. Contemporary magazine reviews are frequently cited for this product with specific issue dates; none of those citations could be verified against the publications themselves, so no review is quoted here.
 
== Restoration ==
 
The case and wrist rests are the parts that yellow, and the wrist rests worst of all because of skin contact. See [[Retrobrite]] before treating anything, and test on the underside of a rest first — the textured surfaces on this keyboard take treatment unevenly.


== Modern Use ==
=== Keypad or sound buttons not working ===
# Connect the keypad on its own. If it works alone but not in the chain, check the ADB cables and shorten the chain.<ref name="g292" />
# The sound buttons need Apple's software (System 6.0.7 or later) on the Macintosh,<ref name="tb" /> and on modern systems a converter or driver that reads the button device at address 7.<ref name="tmk" />
# For Key Caps to show the keypad, Apple's Hardware System Update 2.0 must be installed; Key Caps then follows whichever unit was last touched.<ref name="til13111">Apple Computer, Tech Info Library article 13111, "Apple Adjustable Keyboard: Keypad Access & Key Caps DA (8/93)". Hosted in [[:File:Apple Tech Info Library ADB keyboard and mouse articles.pdf]], PDF p. 15.</ref>


The keyboard and keypad are two ADB devices and therefore need either a converter with two ports or a converter plus a hub. See [[Apple Desktop Bus]] for the protocol timing any converter has to meet.
== Modern use ==
An ADB-to-USB converter has to handle more than one keyboard device on the bus to make the keypad work, and must read the address-7 button device for the sound keys.<ref name="tmk" /> See [[Apple Desktop Bus]] for the protocol.


== See Also ==
== See also ==
* [[Apple Extended Keyboard II]]
* [[Apple Extended Keyboard II]]
* [[Apple Design Keyboard]]
* [[Apple Design Keyboard]]
* [[Apple Desktop Bus]]
* [[Apple Desktop Bus]]
* [[Retrobrite]]


== References ==
== References ==
<references />
<references />


Latest revision as of 13:25, 30 September 2026

Apple Adjustable Keyboard
Apple Adjustable Keyboard M1242 with its separate keypad (wrist rests removed)
Manufacturer Apple Computer, Inc.
Type Ergonomic split keyboard
Release date 1993
Price US$219 (announced list price)
Interface Apple Desktop Bus
Compatible ADB-equipped Macintosh computers, including PowerBooks
Weight 1.055 kg (keyboard), 0.405 kg (keypad), without palm rests
Model M1242 (order no. M1242LL/A)

The Apple Adjustable Keyboard (model M1242) is Apple's split ergonomic keyboard for ADB Macintosh computers, introduced in 1993.[1] The two halves are hinged at the centre rear and swing apart horizontally, up to 30 degrees, with the 6, Y, H and N keys on the right-hand half. The enlarged space bar stays fixed in the centre.[1][2] The keyboard came with removable wrist rests, one for each half, and a separate keypad with its own wrist rest.[1]

The keypad holds the function keys, the navigation cluster and the numeric keys, and connects to the keyboard by a short ADB cable. It can sit on either side of the keyboard.[2] The main keyboard has volume, mute and microphone-record buttons on its right-hand half, the first Macintosh keyboard with sound controls; Apple's software for them needed System 6.0.7 or later. The Escape key, the sound buttons and the function keys are small round keys.[2] TidBITS reported an expected list price of US$219.[2] The FCC ID is BCGM1242 and the layouts are modified ANSI or ISO.[1] Apple sold it as order number M1242LL/A with the keyboard, the keypad, three palm rests, a keypad template, a 3 ft coiled ADB cable, a 1 ft ADB jumper cable and an installer disk.[3]

Specifications

[edit | edit source]
Apple Adjustable Keyboard specifications (Apple)[3]
Item Value
Keys 111 (ANSI), 112 (ISO): main keyboard 68 (ANSI) or 69 (ISO); keypad 43
Main keyboard Escape and power-on keys; volume up, volume down, mute and record keys; green Caps Lock LED; two ADB connectors
Keypad 18-key numeric pad, 15 function keys, four inverted-T cursor keys, six editing keys; two ADB connectors
Supply 5 V DC ±10%; main keyboard 7 mA with the LED off, 19 mA with it on
Typing keys 3.5 mm travel; peak tactile force 0.69 ± 0.25 N at 1.5 mm; minimum life 10 million cycles
Opening angle 0-30°
Slope 5° with the flip feet closed, 12.5° open
Main keyboard size 385.6 mm W × 159 mm D × 37.5 mm H (rear, feet closed)
Keypad size 248.3 mm W × 143.7 mm D × 37.5 mm H
Weight keyboard 1.055 kg (1.223 kg with palm rests); keypad 0.405 kg (0.481 kg with palm rest); 1.7 kg in all
Cables 1.0 m coiled cord and 340 mm cable
Software System 6.0.7 or later
Environment operating 10-40 °C; storage −40 to 47 °C; 95% humidity maximum, non-condensing

Switches

[edit | edit source]

Main keys

[edit | edit source]

The alphanumeric keys use Alps SKFS switches, from the low-profile PCB-mount SKFR/SKFS series.[1] Although low-profile, the switches have the full 3.5 mm travel. The switch is 10.3 mm tall and has an integrated jumper. Its keycap mount is unique to the series, not the common Alps mount, and it is neither pin- nor keycap-compatible with Alps SKFL, so Alps-mount keycaps do not fit and an SKFL is not a substitute.[4]

The variant fitted is SKFS White, Alps model SKFSAA, the tactile member of the series. Its click leaf sits in front of a chamber with an open front wall, so when released the leaf strikes nothing and the switch does not click.[4] The 1994 Alps catalogue nonetheless lists SKFS as clicky.[1]

Function keys and navigation cluster

[edit | edit source]

The function keys and the upper navigation cluster on the keypad are round buttons over what appear to be simple microswitches.[1] TidBITS questioned at launch whether these harder-to-press keys suited an ergonomic keyboard.[2]

ADB devices

[edit | edit source]

The keyboard and the keypad each have two ADB connectors[3] and are separate ADB keyboard devices on the same bus. The keyboard reports Device Handler ID $10 (ANSI), $11 (ISO) or $12 (JIS); the keypad reports $0E.[5] Keyboards default to ADB address $02, and when two devices share a default address the Start Manager gives one of them a new address at startup.[6] The four sound buttons are a third device, at ADB address 7, which the Linux driver lists as the "Adjustable keyboard button device" (original handler ID $02) with microphone, mute, volume-down and volume-up events.[5][7]

Apple's bus limits apply to the set as a whole: 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 ADB port.[8] Do not unplug and reconnect an ADB device while the computer is running: the device reverts to its default address while the computer keeps using the address it assigned at startup.[6]

Maintenance and repair

[edit | edit source]

The keyboard and the keypad are separate assemblies with their own PCBs.[1] Because each is its own ADB device, test them one at a time, each connected directly to the computer, to find which unit is at fault.

Wrist rests

[edit | edit source]

The rests are removable by design. A complete set is three: one for each half of the keyboard and one for the keypad.[1]

Dead or chattering main key

[edit | edit source]
  1. Remove the keycap carefully. The SKFS keycap mount is unique to the series, so a broken keycap or stem cannot be replaced from another Alps family.[4]
  2. Clean the switch with isopropyl alcohol, actuate it repeatedly and let it dry fully.
  3. If that fails, the switch must be desoldered and replaced with another SKFS. Donor Adjustable Keyboards are the usual source; new-old-stock SKFS switches have been sold through online surplus sellers.[4]

Keypad or sound buttons not working

[edit | edit source]
  1. Connect the keypad on its own. If it works alone but not in the chain, check the ADB cables and shorten the chain.[8]
  2. The sound buttons need Apple's software (System 6.0.7 or later) on the Macintosh,[2] and on modern systems a converter or driver that reads the button device at address 7.[5]
  3. For Key Caps to show the keypad, Apple's Hardware System Update 2.0 must be installed; Key Caps then follows whichever unit was last touched.[9]

Modern use

[edit | edit source]

An ADB-to-USB converter has to handle more than one keyboard device on the bus to make the keypad work, and must read the address-7 button device for the sound keys.[5] See Apple Desktop Bus for the protocol.

See also

[edit | edit source]

References

[edit | edit source]
  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Deskthority wiki, "Apple Adjustable Keyboard": part number M1242, FCC ID BCGM1242, modified ANSI or ISO layouts, Alps SKFS switches and microswitches, PCB mount, ADB, weights 1,005 g (keyboard) and 372 g (keypad), which differ from Apple's figures; introduced 1993; description of the hinge, space bar, wrist rests and keypad; photographs of both PCBs. Community wiki, secondary source. Retrieved 2026-09-30.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Adam Engst, "Apple Adjustable Keyboard", TidBITS, 11 January 1993: opening angle up to 30 degrees, split with 6, Y, H and N on the right, fixed enlarged space bar, detachable palm rests, separate extended keypad on a short ADB cable for either side, round keys for Escape, sound and function keys, volume, mute and microphone controls, expected list price US$219, ADB Macs and PowerBooks, sound-key software for System 6.0.7 and later. Retrieved 2026-09-30.
  3. ↑ 3.0 3.1 3.2 Apple Computer, Tech Info Library articles 11226, "Apple Adjustable Keyboard: Description (Discontinued) (5/95)", and 11225, "Apple Adjustable Keyboard: Specifications (Discontinued) (5/95)". Hosted in File:Apple Tech Info Library ADB keyboard and mouse articles.pdf, PDF pp. 10-14.
  4. ↑ 4.0 4.1 4.2 4.3 Deskthority wiki, "Alps SKFR/SKFS series", with part numbers from the 1994 Alps catalogue: 3.5 mm travel, 10.3 mm height, integrated jumper, unique keycap mount, not compatible with SKFL; SKFS White (SKFSAA) tactile, with photographs of the switch from an Apple Adjustable Keyboard and of NOS switches. Retrieved 2026-09-30.
  5. ↑ 5.0 5.1 5.2 5.3 TMK keyboard firmware wiki, "Apple Desktop Bus", "Keyboard Handler ID" (Apple Adjustable Keypad M1242 0x0E; Apple Adjustable Keyboard M1242 0x10, ISO 0x11, JIS 0x12) and "Apple Adjustable Keyboard Media keys" (volume up, volume down, mute and microphone from appliance address 7). Retrieved 2026-09-30.
  6. ↑ 6.0 6.1 Apple Computer, Guide to the Macintosh Family Hardware, 2nd edition (1990), chapter 8, "Apple Desktop Bus", p. 287. Hosted as File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf.
  7. ↑ Linux kernel, drivers/macintosh/adbhid.c, ADB_MISC handler 0x02 "Adjustable keyboard button device". Retrieved 2026-09-30.
  8. ↑ 8.0 8.1 Guide to the Macintosh Family Hardware, 2nd ed., p. 292.
  9. ↑ Apple Computer, Tech Info Library article 13111, "Apple Adjustable Keyboard: Keypad Access & Key Caps DA (8/93)". Hosted in File:Apple Tech Info Library ADB keyboard and mouse articles.pdf, PDF p. 15.


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