22 Aug
2011
22 Aug
'11
1:44 p.m.
On 22 Aug 2011 at 20:19, Tony Duell wrote:
The thing that annoys me is that (as commonly
implemented), it's not
symmetical, which means that null-modem cables are at best a kludge.
OK, you swap TxD with RxD, RTS with CTS and DSR with DTR, but what do
you wap DCD with (and yse, some devices do insist on it). Most of the
time you can strap DCD input on a DTE to whatever is also driving the
DSR signal, but not always.
My memory is getting fuzzy, but were there ever any "gender auto-
detect" cables? In other words, one that automatically determined
via active circuitry the connections between TD and RD and RTS and
CTS? It would seem not to be overly difficult, other than for power
supply issues.
--Chuck