[BRLTTY] the orbit display

[Dave Mielke]

[quoted lines by kendell clark on 2016/09/02 at 21:32 -0500]

>I've often wondered why there isn't a standard usb device class for braille 
>displays like there is for keyboards, mice, etc? 

I'm far from an expert on this, but it could be as simple a there not yet being 
enough of a standard. I rather doubt that any of these devices benefits from 
the kind of mass production and use that keyboards, mice, etc do.

>Is it because each company patents their internals to reduce competition so 
>there's been no opportunity for a standard? 

There may well be some of that. Certain manufacturers definitely have unique 
types of controls. I wouldn't know how much of this is or isn't patented, how 
much of it is competitive, etc.

>A usb or bluetooth standard would make our job easier since we'd only have to 
>support the standard and then add device specifics when needed. 

A lot of it could certainly be done. Each device could, for example, advertise 
how many dots per cell it has, how many banks of cdells it has, etc. There 
could be a standard way to write to a specific subset of cells within a 
specific bank.

I don't know how other screen readers do it, but each brltty driver inrerprets 
key events in a device-specific way but sends them to the core as a three-field 
object: the group to which a key belongs, the key number within that group for 
the key, and whether it's a press or a release. This has proven to be a 
wonderful logical abstraction, and there's no reason that a general protocol 
couldn't work the same way.

Last time I tried email. This time I left voice mail at their customer support 
number. We'll see how they respond.

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Dave Mielke           | 2213 Fox Crescent | The Bible is the very Word of God.
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