Thoughts, info, and images about the PLUM Keyboard.

_{Not precision measurements. Angle when flat / Angle with feet extended.
Images are cropped to fit, click to open full view.}

Still trying out how to format my museum posts, this is a more opinionated one this time. I'm also looking into ways to take better pictures with better lighting. But I will continue with what I have for now.

Summary

The PLUM keyboard is a compact keyboard with a unique ortholinear "PLUM" layout. It interfaces over USB, allowing use with any modern computer. The PLUM keyboard uses Cherry ML switches with laser etched ABS keycaps. It's lightweight and cheap feeling, originally retailing for $139 in late 2003. It was later dropped to $49.99, and then $19.99 by 2008.

PLUM's website, archived 2008. plum.bz web archive

Press release on PLUM's website, archived 2003. plum.bz web archive

More can be read from the Wikipedia page for the PLUM Keyboard.

Thoughts

I can't say that I've actually used this keyboard at all, due to the obvious problem of the layout being completely bizarre. I found mine on eBay a number of years ago.

For me, this is more of a curiosity than a usable keyboard. Though there are ways to convert this to a programmable controller, which maybe I'll look into in the future. At that point it could be programmed into whatever layout works better for you.

Layout

With an ortholinear and highly non-standard layout, this keyboard is completely foreign to my hands. I struggle to use it without having the muscle memory built up for this very limited-use layout. But keyboard layouts are highly subjective and based on preference.

What I do enjoy personally is the form factor of the board. It's compact, but it's also crammed with as many keys that could fit. The dual 3U split spacebar is a cool feature, one that I wish more keyboards adopted. On top of all this, it's also technically a "split" layout, with the two alpha blocks being separated by tab, backspace, comma and period. I enjoy the inclusions of the function row, number row, and the nav cluster. The blank keys output nothing, but do have functional switches in those spaces.

Build

Looking past the layout of the letters, the keyboard's build is fairly unremarkable. It's held together with 3 screws on the bottom, and a few internal clips. The switches are simply inserted into the PCB, no mounting plate or any metal at all. Keycaps are of the same quality as the rest of the case. Lightly textured ABS keys with laser etched legends. These will fade with use. The legends on the keys are a noticeably rougher texture compared to the rest of the key. There are also no homing bars on the home key positions.

Super macro shots of the laser etching.

There is only one green lock light on the keyboard, one for caps locks. The lock light indentation on the top case implies that the other 2 standard lock lights may have been considered at some stage in development. It has 2 grippy rubber feet in the front, and 2 plastic flipout feet in the rear.

Switches

The PLUM keyboard uses Cherry's ML switches, which are notoriously scratchy and prone to binding. I would describe them as probably some of the worst keyboard switches I've ever used, if I'm being honest. The feel is like pushing the entire keycap through very fine wet sand, and running into rocks when the keys bind up. It feels the same as some particularly rough Cherry M9 switches I've encountered, which were literally filled with dust and corrosion.

Close-up of the Cherry ML switches, mounted into the black PCB.

Cherry MY often gets negative responses from people, but even those are significantly smoother and less binding than ML when I compare directly. What I find interesting is that the two 3 unit keys on this keyboard are much more usable. They are still scratchy, but the stabilizer bar removes the binding entirely. I imagine if every switch had its own little stabilizer bar it would be a much better feeling experience, but at that point it's missing the point of a low-cost switch like this. Some modern optical switch keyboards use this idea, like the Razer optical switches. Asus ROG RX switches have an internal cross stabilizer as well.

Extra Stuff

For some reason this keyboard is labeled with a bunch of different companies. It says Genovation, Inc. on the rear label, Datacomp as the manufacturer ID, and Trumpion Microelectronics as the vendor. Trumpion Microelectronics is also a very unfortunate name to have now.

excerpt from lsusb:

idVendor           0x090a Trumpion Microelectronics, Inc.  
idProduct          0x1d20 LCD KeyPad  
bcdDevice            1.00  
iManufacturer           1 Datacomp  
iProduct                2 LCD KeyPad

Alternative Layout Idea

My semi psychotic QWERTY layout idea.

layout concept made with keyboard-layout-editor.com