BTC 53 series

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BTC 53 series

FCC ID	E5X5R5BTC-5339R-0
Manufacturer	BTC
Keyswitches	BTC foam and foil
Interface	XT/AT

BTC 53 series is a series of keyboards from BTC with BTC foam and foil switches. This term (styled as "B T C - 5 3 series") is included on the label of some 53-series keyboards.

53 series encompasses significant variation. There are several case styles, and the sliders can either be supported by a moulded plastic plate (as with BTC dome with slider keyboards), or in plate-mounted inserts as with Realforce keyboards. Both the linear (sub-keycap coil spring) and tactile (with a buckling rubber sleeve). All variants have BTC's 1.25-unit escape key.

The plastic plate under the keycaps has been found in both beige and black, and the sliders can be found in various colours, including white, cyan, yellow and pink.

There is a "MACRO" key in the lower left-hand corner of many 53 series keyboards, of unknown function.

Many (though not all) variations are confirmed Auto-sense capable between XT / AT protocols. Meaning, it's also compatible with modern PCs' with an AT to PS/2 or a AT to USB Adapter, but due to a lack of a Windows Key(s), it may not be ideal to use on Linux and Mac OS without rebinding a different key to serve as one.

Variants

5339

US ANSI, with big-ass enter, "MACRO" key, and backslash to the right of right shift

5349

ISO

5369

US ANSI, without "MACRO" key. FCC ID: E5X5R5BTC-5369

Examples

• Unidentified variant (not listed on label), possibly 5339 — white sliders, beige plate
• Leading Edge–branded 5369, with black plate and cyan sliders
• 5339, with pad-printed legends (depicted below); the "Alt" legends, and the front printed "SysRq" legend are printed in green, with all other text in black; the enter key is notably lighter, with two much lighter springs and two sliders
• Packard Bell F21 T083I, includes larger bezels, OEM brand on the top left corner and a pencil holder - likely an older model produced shortly after the IBM Model M.

Gallery

5339 (linear)

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  Front

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  PCB and foil-covered pads

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  Space bar switch

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  Enter switch

5339R-0

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  Front

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  Front without keycaps

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  Bottom

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  Label

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  Keycaps

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  Sliders

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  Keycap legends

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  Double-shot keycaps

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  Enter key

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  PCB

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  PCB date

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  Controller

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  Slider plate

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  ‎Slider plate with sliders

F21 T083I (Packard Bell OEM)

Front

Back

Trivia

On Linux (particularly on Pop!_OS 20.04 LTS) with Xmodmap, pressing the "macro" Key after entering;"xev | awk -F'[ )]+' '/^KeyPress/ { a[NR+2] } NR in a { printf "%-3s %s\n", $5, $8 }'" in the Terminal, the keycode is registers as "120 NoSymbol".

It's easy to accidentality break the small tabs on the space bar holding on to the wire while removing it, likely due to the age of the plastic. If one of them breaks off, it'll only be stabilized opposite to the broken-off tab

External links

• A Little Bit of Keyboards — btc_5339_coil (Japanese)
• Plate-mounted BTC-5349 (Chinese)
• Plate mounted BTC-5349