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Rebuild with Deskthority + Apple IIGS Technical Procedures + Guide to the Macintosh Family Hardware ch.8. Deleted unsourced dimensions, weight, US$129 price, Pantone 423C, switch force/travel/lifespan figures, 8x11 matrix, 5 ms debounce, 25/50 mA draw, serial-number formats, production timeline, ~750,000-unit production statistics and 2024 market values; corrected fabricated register-2 LED table
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| name        = Apple Desktop Bus Keyboard
| name        = Apple Desktop Bus Keyboard
| image        = [[File:Apple Desktop Bus Keybaord.jpg|250px]]
| image        = [[File:Apple Desktop Bus Keybaord.jpg|250px]]
| caption      = Apple Desktop Bus Keyboard with Alps SKCM Orange switches
| caption      = Apple Desktop Bus Keyboard
| manufacturer = Apple Computer, Inc.
| manufacturer = Apple Computer, Inc. (built by Alps Electric and by SMK)
| type        = Computer keyboard
| type        = Computer keyboard
| release date = September 15, 1986
| release date = September 1986 (with the [[Apple IIGS]])
| discontinued = 1992
| price        = US$129 (retail, keyboard only)
| interface    = [[Apple Desktop Bus]]
| interface    = [[Apple Desktop Bus]]
| compatible  = Apple IIGS, all ADB-equipped Macs
| compatible  = Apple IIGS and all ADB-equipped Macintosh computers
| dimensions  = 440 mm W × 140 mm D × 42 mm H (rear)
| successor    = [[Apple Keyboard (M0116)]]
| weight      = 0.91 kg (2.0 lbs)
| model        = A9M0330 (part number 658-4081 on early Alps units)
| predecessor  = [[Apple IIe Keyboard]] (A2M2003)
| successor    = [[Apple Keyboard (M0116)]] (M0116)
| model        = A9M0330, 658-4081
}}
}}
<templatestyles src="Template:StyledTable/styles.css" />
The '''Apple Desktop Bus Keyboard''' was the first keyboard to use the [[Apple Desktop Bus]], introduced in September 1986 with the [[Apple IIGS]]. Because it is nearly always found with that machine it is commonly called the '''Apple IIGS Keyboard'''. Deskthority records three firsts for the IIGS and its keyboard: the Apple Desktop Bus itself, including a second port for daisy-chaining the mouse; a '''power button on the keyboard'''; and the "Platinum" colour scheme.<ref name="dt">"Apple Desktop Bus Keyboard", [https://deskthority.net/wiki/Apple_Desktop_Bus_Keyboard Deskthority wiki]. Model A9M0330, part number 658-4081 on the older Alps version, FCC IDs BCG5ARA9M0330 (Alps) and BCG47FA9M0330 (SMK); manufacture by Alps Electric in Japan and by SMK in Taiwan; Alps SKCM Orange and Salmon switches with an Alps SKCL Lock for Caps Lock; SMK Alps-mount switches with SMK PCB part number 2J-M9020-02B and double-shot keycaps; years of production 1986–1992; controller date codes 8844 (SMK example) and 9041 (salmon Alps example); and the observation that the yellowing behaviour suggests ABS for the case and space bar with a different material for the remaining keycaps. '''Community wiki, cited as a secondary source''' for part numbers, FCC identifiers, manufacturers and switch types; it is photograph-backed and states explicitly where it is speculating.</ref>


The '''Apple Desktop Bus Keyboard''' was the first keyboard to implement Apple's new [[Apple Desktop Bus]] interface, introduced alongside the [[Apple IIGS]] computer on September 15, 1986. Often referred to as the '''Apple IIGS Keyboard''', it pioneered several Apple firsts: the ADB interface, dual ADB ports for daisy-chaining, an integrated power button, and the introduction of the Snow White design language. The keyboard was manufactured in two distinct variants—one in Japan with Alps switches and another in Taiwan with SMK switches—both sharing the same external appearance but differing significantly in internal construction and keycap manufacturing methods.
It was built in two places, by two different manufacturers, with two different switch mechanisms. The cases look the same; the insides do not.


== Historical Context ==
== Variants ==


The Apple Desktop Bus Keyboard represented a convergence of Apple's computer lines, bridging the Apple II and future Macintosh families. Developed during 1985-1986 as part of the Apple IIGS project, it embodied Apple's vision for a unified peripheral ecosystem. The keyboard introduced the ADB interface months before it appeared on any Macintosh computer, establishing the protocol that would serve Apple for the next thirteen years.
=== Alps (made in Japan) ===
Alps-built keyboards use '''Alps SKCM Orange''' and '''Alps SKCM Salmon''' switches, with an '''Alps SKCL Lock''' latching switch for Caps Lock; on at least one orange-Alps example that lock switch is cream rather than the usual colour.<ref name="dt" />


The keyboard's design marked Apple's first implementation of the Snow White design language developed by Hartmut Esslinger's Frog Design team. The introduction of "Platinum" gray coloring on the IIGS and its peripherals established the color scheme that would define Apple products through the 1990s. This represented a significant departure from the beige computers of the early 1980s, positioning Apple as a design-focused company.
Most of these carry a simple rear label with part number '''658-4081'''. At some point the label was brought into line with the Taiwanese version and reads model '''A9M0330'''. Deskthority notes that the keyboards with the newer label appear to be the ones with salmon switches — '''and says explicitly that this is speculation.'''<ref name="dt" /> It is repeated here as speculation, not as a dating rule. Apple published no variant table, and the orange-to-salmon change cannot be pinned to a date from any source seen here.


== Design Features ==
=== SMK (made in Taiwan) ===
The Taiwanese keyboards use white tactile '''SMK Alps-mount''' switches. Apple's own ''Apple IIGS Technical Procedures'' calls the switches SMK, which is the strongest evidence available.<ref name="a2gs">''Apple IIGS Technical Procedures'', Apple Computer, Inc., section 5 (page 5.10), cited via [https://deskthority.net/wiki/Apple_Desktop_Bus_Keyboard Deskthority]. Apple's own service documentation identifies the switches in the Taiwan-built keyboard as SMK.</ref> The PCB carries an SMK part number, '''2J-M9020-02B'''. Keycaps on this version are '''double-shot moulded''' and slightly darker than on the Alps version.<ref name="dt" />


=== Physical Design ===
Photographed controller date codes give a rough production window: '''8844''' on an SMK example and '''9041''' on a salmon-Alps example.<ref name="dt" /> Deskthority gives the overall production range as '''1986–1992'''.<ref name="dt" />
The keyboard embodied the Snow White design language principles:
* '''Horizontal grooves:''' Decorative lines creating visual texture
* '''Slanted profile:''' Front-to-back angle for ergonomic typing
* '''Platinum coloring:''' Warm gray tone (Pantone 423C equivalent)
* '''Unified aesthetic:''' Matched Apple IIGS system unit design


The 81-key layout represented a transitional design, incorporating elements from both Apple II and Macintosh keyboard traditions:
=== Telling them apart without opening the case ===
* '''Escape key:''' First appearance on an Apple keyboard
The FCC ID on the rear label is the cleanest discriminator: '''BCG5ARA9M0330''' for the Alps version and '''BCG47FA9M0330''' for the SMK version.<ref name="dt" />
* '''Control key:''' Positioned left of 'A' (Apple II tradition)
* '''Command keys:''' Open and closed Apple logos
* '''Option key:''' Introduced for special characters
* '''Power button:''' Upper right corner position


=== Layout Peculiarities ===
== Materials ==
Several non-standard key arrangements distinguished this keyboard:
* '''Arrow keys:''' Single row arrangement (← → ↓ ↑)
* '''Tilde/Grave:''' Positioned left of spacebar
* '''Caps Lock:''' Lower left corner placement
* '''Delete key:''' Labeled as "Delete" (not Backspace)
* '''Return key:''' Backward L-shape configuration


== Manufacturing Variants ==
Deskthority infers from yellowing behaviour that the case and space bar are ABS while the remaining keycaps are a different material, probably PBT.<ref name="dt" /> That is an observation from photographs, not a published specification, and it matters for restoration: see [[Retrobrite]] before treating anything, and expect the case and space bar to respond differently from the rest of the keycaps.


=== Japan Variant (658-4081) ===
Apple published no dimensions, weight, retail price or production figures for this keyboard that could be found, and none are stated here.


'''Production Period:''' 1986-1991
== ADB Behaviour ==


'''Identification:'''
The keyboard is an ordinary ADB encoded device. Apple's published protocol figures, which apply to it:<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>
* Label marked "Made in Japan"
* Part number 658-4081 or 825-1301-A
* Early units: Simple rear label
* Later units: A9M0330 designation added


'''Switch Technology:'''
* '''Default address $02''' — the address Apple reserves for encoded devices.
* '''Early production (1986-1989):''' Alps SKCM Orange
* '''Register 0''' holds '''two''' key events in 16 bits: bit 15 key status for the first key (0 = down), bits 14–8 its 7-bit key code, bit 7 key status for the second key, bits 6–0 its key code. Two-key reporting is a property of this register format, not of the switch matrix.
** Orange-colored sliders
* '''Register 2''' on an Apple Standard Keyboard carries modifier-key status only — Delete, Caps Lock, Reset, Control, Shift, Option, Command, with 0 meaning "down". It carries '''no LED bits'''; those exist only on the Extended Keyboard.
** Tactile, non-clicky operation
* Power-on is not an ADB message at all. The power key works by momentarily grounding '''pin 2 (POWER.ON)''' of the connector to pin 4, and that only does anything on machines wired for it — on other models pin 2 is not connected.
** 70g actuation force


* '''Late production (1989-1991):''' Alps SKCM Salmon
The two ADB ports are electrically in parallel; either can face the computer.
** Pink-salmon colored sliders
** Identical feel to Orange
** Slightly different internal construction
'''Keycaps:'''
* Material: PBT plastic (except spacebar: ABS)
* Manufacturing: Dye sublimation
* Color: Uniform platinum gray
* Profile: Apple standard (similar to Cherry)
* Stabilizers: Brown Alps-type clips


'''Construction Details:'''
== Maintenance and Repair ==
* Internal plate: Steel, painted
* PCB: Single-sided with jumper wires
* Controller: Custom Apple ASIC
* Assembly: Three screws with washers


=== Taiwan Variant (A9M0330) ===
=== Before you start ===
Both switch types here are mechanical and both are obsolete. '''Harvesting is the only realistic source of replacements''', and the two types are not interchangeable with each other's keycaps in practice even though SMK uses an Alps-compatible mount, because the keycap sets differ in colour and moulding.<ref name="dt" />


'''Production Period:''' 1987-1992
=== Dead or intermittent key ===
# Confirm on a known-good ADB machine first — a dead ADB port or an open logic-board ADB fuse looks identical to a dead keyboard.
# Remove the keycap and flood the switch with 90%+ isopropyl alcohol, actuating repeatedly, then let it evaporate fully before testing.
# If that does not fix it, the switch has to come out. Both Alps SKCM and SMK switches open at four retention tabs; the contacts are the usual failure.


'''Identification:'''
=== Caps Lock stuck ===
* Label marked "Made in Taiwan"
The Caps Lock position is a latching switch, Alps SKCL Lock on the Alps boards.<ref name="dt" /> It is mechanically different from the surrounding switches and a normal switch will not substitute — it will type, but it will not latch.
* Model number A9M0330 prominently displayed
* Consistent labeling throughout production


'''Switch Technology:'''
=== Cable ===
* '''SMK second-generation Alps mount'''
The ADB lead is the usual failure point at the strain relief. Check continuity of all four conductors end to end while flexing. A generic 4-pin mini-DIN ADB lead substitutes.
** White-colored sliders
** Tactile, non-clicky operation
** 65g actuation force (lighter than Alps)
** Cross-mount compatible with Alps keycaps
'''Keycaps:'''
* Material: ABS plastic
* Manufacturing: Double-shot injection molding
* Color: Slightly darker gray than Japan variant
* Bottom: Dark gray (two-tone appearance)
* Stabilizers: White SMK-type clips


'''Construction Details:'''
=== Nothing at all ===
* PCB: Includes EMI shielding (tin foil layer)
* Measure '''+5 V at pin 3 against pin 4''' of the ADB port on the computer.
* Part number: SMK 2J-M9020-02B
* Pin 1 should idle high, held up by the '''470 Ω''' pull-up on the computer's logic board.<ref name="gmfh" />
* Controller: Socketed ROM chip (341-0124)
* Keep the chain short: Apple recommends '''no more than three devices''' daisy-chained on one ADB port, and no more than 5 m of cable, because of connector resistance and signal degradation.<ref name="gmfh" />
* Assembly: Three screws (washers optional)


== Technical Specifications ==
== Modern Use ==


=== Physical Specifications ===
ADB-to-USB conversion is the usual route. The power key generally needs remapping because it is a hardware line rather than a key code. Commercial adapters of the period are discontinued and community converters come and go; check that whatever you use implements Apple's timing rather than approximating it, and see [[Apple Desktop Bus]] for the figures.
* '''Dimensions:''' 440mm × 140mm × 42mm
* '''Weight:''' 0.91kg (Japan) / 0.86kg (Taiwan)
* '''Cable:''' Coiled ADB, 1.2m extended
* '''Keys''' 81 total
* '''Typing angle''' 6 degrees
 
=== Electrical Specifications ===
* '''Interface''' Apple Desktop Bus (ADB)
* '''Power consumption''' 25mA typical, 50mA maximum
* '''Operating voltage''' 4.75V - 5.25V
* '''Data rate''' 10 kbit/s maximum
 
=== ADB Protocol Implementation ===
* '''Device type''' Keyboard
* '''Default address''' $2
* '''Handler ID''' $01 (Standard protocol)
* '''Registers'''
** Register 0: Key event data (2 bytes)
** Register 1: Reserved
** Register 2: LED status and modifiers
** Register 3: Device ID and address
=== Key Matrix ===
* '''Matrix size''' 8×11
* '''Rollover''' 2-key guaranteed
* '''Ghosting prevention''' Diode per switch
* '''Debounce''' Hardware (5ms)
 
== Switch Specifications ==
 
=== Alps SKCM Orange/Salmon ===
'''Specifications'''
* Type: Tactile, non-clicky
* Actuation force: 70g ± 10g
* Pre-travel: 2.0mm
* Total travel: 3.5mm
* Lifespan: 10 million actuations
 
'''Characteristics'''
* Smooth tactile bump
* Minimal wobble
* Consistent feel across keyboard
* Self-cleaning contacts
 
=== SMK Second Generation ===
'''Specifications'''
* Type: Tactile, non-clicky
* Actuation force: 65g ± 10g
* Pre-travel: 2.0mm
* Total travel: 3.5mm
* Lifespan: 20 million actuations
 
'''Characteristics'''
* Lighter than Alps
* More pronounced tactility
* Slightly scratchier feel
* Cross-mount Alps compatible
 
=== Alps SKCL Lock (Caps Lock) ===
All variants used the Alps SKCL Lock switch:
* Mechanical latching mechanism
* Physical lock when engaged
* Cream or white housing
* Not user-replaceable with standard switch
 
== Production Information ==
 
=== Serial Number Format ===
'''Japan (658-4081)'''
* Format: NNNNNN (six digits)
* Example: 380504, 318537
 
'''Taiwan (A9M0330)'''
* Format: PPYWWNNNNNN
* PP: Production facility
* Y: Year (7=1987, 8=1988, etc.)
* WW: Week number
* NNNNNN: Sequential number
 
=== Production Timeline ===
* '''1986''' Initial release with Apple IIGS (Japan only)
* '''1987''' Taiwan production begins
* '''1989''' Transition from Orange to Salmon Alps (Japan)
* '''1990''' Peak production year
* '''1991''' Japan production ends
* '''1992''' Final units produced (Taiwan)
 
=== Manufacturing Differences ===
 
{| class="wikitable" style="width:85%; text-align:center;"
|+'''Component Comparison'''
! Component !! Japan Variant !! Taiwan Variant
|-
| Switches || Alps SKCM Orange/Salmon || SMK Second Generation
|-
| Keycaps || PBT, dye-sublimated || ABS, double-shot
|-
| Stabilizers || Brown Alps clips || White SMK clips
|-
| PCB || No shielding || EMI foil shielding
|-
| ROM || Soldered or socketed || Always socketed
|-
| Assembly || Screws with washers || Screws, washers optional
|-
| Weight || 0.91kg || 0.86kg
|-
| Production || 1986-1991 || 1987-1992
|}
 
== Keycap Design ==
 
=== Row Profiles ===
The keyboard used different stem heights for each row:
* '''Number row''' Tallest stems, switches mounted vertically
* '''QWERTY row''' Standard height
* '''Home row''' Slightly shorter
* '''Bottom row''' Shortest stems
* '''Spacebar''' Custom profile with multiple mount points
 
=== Typography ===
* '''Font''' Univers 57 Condensed
* '''Style''' Regular (not italic like later Apple keyboards)
* '''Alignment''' Centered on keycap
* '''Special keys''' Icon-based legends (Command, Option)
 
=== Manufacturing Quality ===
'''Japan variant (dye-sublimation)'''
* Permanent legends, wear-resistant
* Uniform color throughout keycap
* PBT resistant to yellowing
* Sharp, precise legends
 
'''Taiwan variant (double-shot)'''
* Legends cannot wear off
* Two-tone appearance (gray top, dark bottom)
* ABS prone to yellowing
* More structural support for stems
 
== Software Compatibility ==
 
=== Operating Systems ===
* '''Apple IIGS''' ProDOS 16, GS/OS
* '''Mac OS''' System 3.2 through Mac OS 9.2.2
* '''Apple IIe Card''' Full compatibility
* '''A/UX''' Native support
* '''NeXT''' Limited compatibility
 
=== Key Mapping ===
* '''Open Apple →''' Command
* '''Closed Apple →''' Option
* '''Delete →''' Backspace function
* '''Power key''' Direct system control
 
=== Special Functions ===
* '''Control-Open Apple-Reset''' System reset
* '''Open Apple-Control-Escape''' Programmer's switch
* '''Power button''' Cold boot from off state
 
== Maintenance & Repair ==
 
=== Disassembly ===
 
'''Required tools'''
* Phillips screwdriver #1
* Plastic spudger
* Isopropyl alcohol 90%+
 
'''Procedure'''
# Remove three case screws (note washer presence)
# Separate case halves carefully
# Disconnect cable if removable
# Remove PCB screws
# Lift PCB assembly
 
=== Switch Cleaning ===
 
'''Alps switches'''
# Remove keycap
# Apply isopropyl alcohol drops
# Actuate repeatedly
# Allow complete drying
 
'''SMK switches'''
# Similar process to Alps
# May require disassembly for deep cleaning
# Lubrication not recommended
 
=== Common Problems ===
 
{| class="wikitable" style="width:80%; text-align:center;"
|+'''Troubleshooting Guide'''
! Problem !! Cause !! Solution
|-
| Keys not registering || Dirty switch contacts || Clean with alcohol
|-
| Repeating keys || Worn switch || Replace switch
|-
| ADB not recognized || Cable damage || Test continuity, replace
|-
| Yellowing || UV exposure, age || Retrobright treatment
|-
| Caps Lock stuck || Latch mechanism worn || Replace SKCL switch
|-
| Scratchy feel || Contamination || Disassemble and clean
|}
 
=== Parts Availability ===
* '''Alps switches''' Harvest from donor boards
* '''SMK switches''' Unique to this model
* '''Keycaps''' Not interchangeable between variants
* '''Stabilizers''' Variant-specific
* '''Cable''' Generic ADB cable compatible
 
== Modern Usage ==
 
=== ADB to USB Adapters ===
* '''Griffin iMate''' Original solution (discontinued)
* '''Wombat''' Current best option
* '''TMK converter''' DIY solution
* '''Drakware''' Premium cables
 
=== Compatibility Notes ===
* Power button may not function
* All keys map correctly
* No driver needed for basic function
* Special keys require remapping software
 
=== Restoration ===
 
'''Retrobrighting'''
* More effective on Japan variant (PBT)
* Taiwan variant (ABS) prone to brittleness
* Use hydrogen peroxide method
* Monitor carefully to prevent damage
 
'''Switch restoration'''
* Orange/Salmon Alps highly valued
* Ultrasonic cleaning recommended
* Springs can be replaced
* Slider replacement difficult
 
== Collector Information ==
 
=== Market Value (2024) ===
* '''Japan/Orange Alps''' $200-400
* '''Japan/Salmon Alps''' $150-300
* '''Taiwan/SMK''' $100-200
* '''Mint/boxed''' +100% premium
 
=== Authentication ===
* Verify label format matches variant
* Check switch type with keycap removal
* Confirm keycap manufacturing method
* Inspect stabilizer clip color
 
=== Desirability Factors ===
* Orange Alps most sought after
* Complete original cable important
* Minimal yellowing commands premium
* Original packaging extremely rare
 
== Cultural Impact ==
 
The Apple Desktop Bus Keyboard introduced design and technical elements that influenced Apple's keyboard designs for over a decade. The dual ADB ports established the precedent for keyboard-integrated hubs, while the power button placement became standard on Apple keyboards until the early 2000s.
 
The keyboard's unusual layout, particularly the single-row arrow keys and unconventional modifier key positions, proved controversial. These quirks were quickly addressed in the successor M0116, demonstrating Apple's responsiveness to user feedback while maintaining design innovation.
 
For many users, this was their introduction to mechanical keyboards, with the Alps switches providing a typing experience that many still consider superior to modern alternatives. The keyboard's association with the Apple IIGS, used extensively in schools during the late 1980s and early 1990s, created lasting nostalgic connections for a generation of computer users.
 
== Production Statistics ==
 
Estimated production numbers based on serial number analysis:
* '''Total production''' ~750,000 units
* '''Japan variant''' ~400,000 (53%)
* '''Taiwan variant''' ~350,000 (47%)
* '''Orange Alps''' ~200,000 units
* '''Salmon Alps''' ~200,000 units
* '''SMK switches''' ~350,000 units
 
== Legacy ==
 
The Apple Desktop Bus Keyboard established several precedents:
* First implementation of ADB protocol
* Introduction of Snow White design language
* Established dual-port keyboard design
* Pioneered keyboard power button integration
 
While its non-standard layout was controversial, the build quality and switch technology represented a high point in Apple keyboard construction. The Orange Alps switches in particular have achieved legendary status among keyboard enthusiasts, with these switches commanding premium prices when harvested for custom keyboard projects.
 
The keyboard's role in introducing ADB cannot be understated—this interface would serve Apple computers for thirteen years, making it one of the longest-lived peripheral standards in personal computing history. The backward compatibility maintained throughout the ADB era meant this keyboard could be used with Macintosh systems released a decade after its discontinuation.


== See Also ==
== See Also ==
* [[Apple Desktop Bus]]
* [[Apple Desktop Bus]]
* [[Apple Desktop Bus Mouse]]
* [[Apple Keyboard (M0116)]]
* [[Apple Keyboard|Apple Extended Keyboard]]
* [[Apple IIGS]]
* [[Apple IIGS]]
* [[Apple Keyboard]] (M0116)
* [[Apple Extended Keyboard]]


{{Navbox-AppleVintageAccessories}}
== References ==
 
<references />
 
{{Navbox-AppleVintageAccessories|state=collapsed}}


[[Category:Apple Vintage Accessories]]
[[Category:Apple Vintage Accessories]]
[[Category:Apple Desktop Bus]]
[[Category:Apple Desktop Bus]]

Revision as of 19:02, 23 September 2026

Apple Desktop Bus Keyboard
Apple Desktop Bus Keyboard
Manufacturer Apple Computer, Inc. (built by Alps Electric and by SMK)
Type Computer keyboard
Interface Apple Desktop Bus
Compatible Apple IIGS and all ADB-equipped Macintosh computers
Successor Apple Keyboard (M0116)
Model A9M0330 (part number 658-4081 on early Alps units)

The Apple Desktop Bus Keyboard was the first keyboard to use the Apple Desktop Bus, introduced in September 1986 with the Apple IIGS. Because it is nearly always found with that machine it is commonly called the Apple IIGS Keyboard. Deskthority records three firsts for the IIGS and its keyboard: the Apple Desktop Bus itself, including a second port for daisy-chaining the mouse; a power button on the keyboard; and the "Platinum" colour scheme.[1]

It was built in two places, by two different manufacturers, with two different switch mechanisms. The cases look the same; the insides do not.

Variants

Alps (made in Japan)

Alps-built keyboards use Alps SKCM Orange and Alps SKCM Salmon switches, with an Alps SKCL Lock latching switch for Caps Lock; on at least one orange-Alps example that lock switch is cream rather than the usual colour.[1]

Most of these carry a simple rear label with part number 658-4081. At some point the label was brought into line with the Taiwanese version and reads model A9M0330. Deskthority notes that the keyboards with the newer label appear to be the ones with salmon switches — and says explicitly that this is speculation.[1] It is repeated here as speculation, not as a dating rule. Apple published no variant table, and the orange-to-salmon change cannot be pinned to a date from any source seen here.

SMK (made in Taiwan)

The Taiwanese keyboards use white tactile SMK Alps-mount switches. Apple's own Apple IIGS Technical Procedures calls the switches SMK, which is the strongest evidence available.[2] The PCB carries an SMK part number, 2J-M9020-02B. Keycaps on this version are double-shot moulded and slightly darker than on the Alps version.[1]

Photographed controller date codes give a rough production window: 8844 on an SMK example and 9041 on a salmon-Alps example.[1] Deskthority gives the overall production range as 1986–1992.[1]

Telling them apart without opening the case

The FCC ID on the rear label is the cleanest discriminator: BCG5ARA9M0330 for the Alps version and BCG47FA9M0330 for the SMK version.[1]

Materials

Deskthority infers from yellowing behaviour that the case and space bar are ABS while the remaining keycaps are a different material, probably PBT.[1] That is an observation from photographs, not a published specification, and it matters for restoration: see Retrobrite before treating anything, and expect the case and space bar to respond differently from the rest of the keycaps.

Apple published no dimensions, weight, retail price or production figures for this keyboard that could be found, and none are stated here.

ADB Behaviour

The keyboard is an ordinary ADB encoded device. Apple's published protocol figures, which apply to it:[3]

  • Default address $02 — the address Apple reserves for encoded devices.
  • Register 0 holds two key events in 16 bits: bit 15 key status for the first key (0 = down), bits 14–8 its 7-bit key code, bit 7 key status for the second key, bits 6–0 its key code. Two-key reporting is a property of this register format, not of the switch matrix.
  • Register 2 on an Apple Standard Keyboard carries modifier-key status only — Delete, Caps Lock, Reset, Control, Shift, Option, Command, with 0 meaning "down". It carries no LED bits; those exist only on the Extended Keyboard.
  • Power-on is not an ADB message at all. The power key works by momentarily grounding pin 2 (POWER.ON) of the connector to pin 4, and that only does anything on machines wired for it — on other models pin 2 is not connected.

The two ADB ports are electrically in parallel; either can face the computer.

Maintenance and Repair

Before you start

Both switch types here are mechanical and both are obsolete. Harvesting is the only realistic source of replacements, and the two types are not interchangeable with each other's keycaps in practice even though SMK uses an Alps-compatible mount, because the keycap sets differ in colour and moulding.[1]

Dead or intermittent key

  1. Confirm on a known-good ADB machine first — a dead ADB port or an open logic-board ADB fuse looks identical to a dead keyboard.
  2. Remove the keycap and flood the switch with 90%+ isopropyl alcohol, actuating repeatedly, then let it evaporate fully before testing.
  3. If that does not fix it, the switch has to come out. Both Alps SKCM and SMK switches open at four retention tabs; the contacts are the usual failure.

Caps Lock stuck

The Caps Lock position is a latching switch, Alps SKCL Lock on the Alps boards.[1] It is mechanically different from the surrounding switches and a normal switch will not substitute — it will type, but it will not latch.

Cable

The ADB lead is the usual failure point at the strain relief. Check continuity of all four conductors end to end while flexing. A generic 4-pin mini-DIN ADB lead substitutes.

Nothing at all

  • Measure +5 V at pin 3 against pin 4 of the ADB port on the computer.
  • Pin 1 should idle high, held up by the 470 Ω pull-up on the computer's logic board.[3]
  • Keep the chain short: Apple recommends no more than three devices daisy-chained on one ADB port, and no more than 5 m of cable, because of connector resistance and signal degradation.[3]

Modern Use

ADB-to-USB conversion is the usual route. The power key generally needs remapping because it is a hardware line rather than a key code. Commercial adapters of the period are discontinued and community converters come and go; check that whatever you use implements Apple's timing rather than approximating it, and see Apple Desktop Bus for the figures.

See Also

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 "Apple Desktop Bus Keyboard", Deskthority wiki. Model A9M0330, part number 658-4081 on the older Alps version, FCC IDs BCG5ARA9M0330 (Alps) and BCG47FA9M0330 (SMK); manufacture by Alps Electric in Japan and by SMK in Taiwan; Alps SKCM Orange and Salmon switches with an Alps SKCL Lock for Caps Lock; SMK Alps-mount switches with SMK PCB part number 2J-M9020-02B and double-shot keycaps; years of production 1986–1992; controller date codes 8844 (SMK example) and 9041 (salmon Alps example); and the observation that the yellowing behaviour suggests ABS for the case and space bar with a different material for the remaining keycaps. Community wiki, cited as a secondary source for part numbers, FCC identifiers, manufacturers and switch types; it is photograph-backed and states explicitly where it is speculating.
  2. ↑ Apple IIGS Technical Procedures, Apple Computer, Inc., section 5 (page 5.10), cited via Deskthority. Apple's own service documentation identifies the switches in the Taiwan-built keyboard as SMK.
  3. ↑ 3.0 3.1 3.2 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.


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