On Feb 11, 18:23, Tothwolf wrote:
> There are also Differential versions of Fast, Ultra, Wide, and
Ultra-Wide.
> These use a "high voltage" (+-12VDC IIRC) signaling that is *NOT*
> compatible with standard devices.
That's not correct. Normal differential, sometimes called high voltage
differential to distinguish it from LVDS still uses 5V, same as
single-ended. It uses thresholds of 2V and 3V, zero-referenced, with a
resistive divider asthe terminator, 150 ohms from ground to signal-, 150
ohms from +V (termpower supply) to signal+, and 330 ohms between signal-
and signal+.
> You will literally fry any non HVD
> devices if you connect a HVD drive to the same bus. Ultra2 and newer have
> a Low Voltage Differential bus
Similar to normal differential but based on 3.3V instead of 5V, and the
maximum bus length is halved.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Tue Feb 12 2002 - 02:23:58 GMT