Actually to the credit of IBM, the RS232 standard was in a total shambles before PC's. Then when IBM made the first serial adapter for the PC they made it with the right pinout and even the right sex of connector and made it as DTE. It was at that time possible to connect a modem to a PC with a straight 25 wire straight through cable!! (almost untold of in the world of small computers of that time).

Thankgoodness the PC has stayed true to the original IBM designs for RS232 (albeit somewhat bastardized when IBM introduced 9-pin COMM port on the first PC/AT.).

The original true RS232 of course was designed around the venerable DB-25 connector.

Michael Karas