27 Oct
2012
27 Oct
'12
1:40 a.m.
On 26 October 2012 21:22, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Avoid pins 4 and 5 for the serial port, that pair is
commonly used for a
single telephone line.
Haiving ringing voltaeg (around 75-100V AC) appear between RS232 port
pins can really ruin your day.
Indeed. One of my predecessors had implemented a system at several
sites where he used actual BT telephone sockets and cables to link
serial terminals/PCs up, albeit mounted upside down... The catalyst
for changing this all over to something less stupid was when the FD of
one company was shuffling his desk about, and reconnected the
identical cables running from his fax machine and brand new (486) PC
(running a terminal emulator) the wrong way around... Bye bye
integrated motherboard..