Re: [microsound] OT- HW: one keypad controlling 2 computers over usb?

[Steve Adam <spectro7@xxxxxxxxxxxx>]

devslashnull <dev@xxxxxxxxxxx> wrote:

>greetings all,
>
>I have what appears to me to be a somewhat unique problem to solve 
>involving wiring a USB cable to allow one keyboard (qwerty type as 
>opposed to MIDI/musical) to send messages (keystrokes) to 2 
>computers at the same time.
>

snip

>I have gotten some responses on other lists telling me this is 
>impossible, citing timing and sync issues over USB, and refering to 
>some kind of Master-Slave relationship (NO, not from the BDSM list ).


I am no USB expert but am also under the impression that it is not 
possible for a USB device to successfully connect to two hosts unless 
the connection is managed by one of the hosts.The following is quoted 
from:
http://www.beyondlogic.org/usbnutshell/usb1.htm

The Universal Serial Bus is host controlled. There can only be one 
host per bus. The specification in itself, does not support any form 
of multimaster arrangement. However the On-The-Go specification which 
is a tack on standard to USB 2.0 has introduced a Host Negotiation 
Protocol which allows two devices negotiate for the role of host. 
This is aimed at and limited to single point to point connections 
such as a mobile phone and personal organiser and not multiple hub, 
multiple device desktop configurations.

>Anyone ever do/try this? Alternative approaches to what I am trying 
>to accomplish?

Assuming you are willing to spend a little money on a solution,  a 
wireless keyboard and two matching receivers ( or two identical 
wireless keyboard/receiver kits) might have a better chance of 
success assuming the built-in channel assignment arrangement  is not 
too 'intelligent' to be fooled.

S.