Don et al,
For my previous job, I had copies of all of the EIA and RS specifications for serial interfaces.
The original RS232 specs call for the 25 pin connector (DB25). The current version (-E or -F I think) also introduces the high density 26 connector (looks like SCSI-2, but that's whole other set of specifications!).
The DE9 was standardized in EIA-574, and I think originally appeared in the IBM PC-XT or some other early version.
The 8 position modular plug is specified in EIA-561. RJ45 is the common name, but that designation is really only for a specific application and wiring pinout, and since we're using the proper names for the D-Sub connectors, well...
RS232 is one of the few specifications to actually define mechanical (connector), electrical (voltage levels etc) and functional (TXD, RXD, RTS etc) parameters. The DB25 also appears in RS530, which is a mechanical/functional spec only, the electrical spec can be RS422 (a balanced interface) or V.35 (balanced data and timing, unbalanced control), or any other signal you want. I can't remember if 561 and 574 are also complete specs, but I think they are.
73,
Dave AA3EE
>From: Don Wilhelm <
[hidden email]>
>Date: Mon Mar 27 16:10:46 CST 2006
>To:
[hidden email],
[hidden email]
>Subject: RE: [Elecraft] serial port remote control of K2 question
>This question gives me cause to post my occasional RANT for the protection
>of your K2.
>
>CAUTION! Be Aware - your K2 can be damaged by connecting some of the RS-232
>signals.
>
>The K2 AUX IO port is NOT an RS232 port!
>
>Although the port has 3 pins that are compatible with RS-232 levels (RXD,
>TXD, and Signal Ground), there are other signals present on that connector
>which are for passing information to other Elecraft devices, and if these
>lines are subjected to the +/- 15 volt or greater voltages that may appear
>in an RS-232 interface, circuits inside the K2 may be damaged. Read the
>label on that K2 connector literally, it is properly labeled 'AUX IO', and
>that does not mean RS-232.
>
>It is unfortunate that the PC world uses these DE9 connectors for RS-232,
>and it is (was) a PC world implementation only, real RS-232 ports use the
>DB9 or the RJ45 connectors - these are defined in the RS-232 standard, the
>DE9 connector is not in the latest standard publication that I am aware of.
>
>73,
>Don W3FPR
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