Date   : Wed, 06 Oct 2004 11:19:55 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: XFER cable (signal voltages)

Whilst on the subject of xfer cables, is there any need to worry about
signal voltages? Doesn't the RS232 spec omit signal voltages for logic
high and low (although I have a feeling PCs typically - always? - use
+/- 12V signals) ?

What about the BBC side though? Does RS423 specify voltages? I know some
old TTL serial equipment uses 0V for logic low and +5V for logic high on
the serial lines, which can cause problems talking to systems expecting
+/- 12V for signals (e.g. +5V might not be enough for the remote system
to detect as a logic high)

Am I worrying about nothing? It might explain why some people are having
problems with transfers though.

cheers,

Jules