🚀 go-pugleaf

k...@cs.rochester.edu (Ken Yap) writes:

>... I was suddenly posessed to
>take a soda can ring tab and short pins 2 and 3 of the RS232 connector
>at the back of a Teleray T1061. This meant that the transmit was looped
>back to the receive.  Till this day I still wonder why I didn't blow
>any driver chips.

The RS-232 spec is kinda funny. While they omitted a lot of things, it was at
least partially based on real-world experience. One section of it *requires*
that you be able to short any pin to any other pin without hurting the interface
circuitry.

What can be real fun is hooking one of these modern RS-232 gizmos up to an 
old unit. The spec allows mark to be anything from +5v to +25v, and space
to be -5v to -25v (I may have mark and space reversed).At the full +/- 25v
most modern PC equipment gets more than a little unhappy.
-- 
Leonard Erickson		...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I'm all in favor of keeping dangerous weapons out of the hands of fools.
Let's start with typewriters." -- Solomon Short