Ready made 9pin male to 9 pin female RS232 cable. 5 metres. low capacitance / high speed.

25 pin Male to RJ45 socket adaptrer
25 pin Female to RJ45 socket adapter
9 pin Male to RJ45 adapter
9 pin Female to RJ45 adapter

25 pin male to male gender changer
25 pin female to female gender changer
9 pin male to male gender changer
9 pin female to female gender changer

9 pin female to 25 pin male (PC to standard connector)

25 pin back to back housing.

Multi-Lamp check tester
Breakout box
 

USB to RS232 multiport. Belkin sell these - so presumably do Lindy.

RS232 adapter on PCI (probably 2 ports and 1 parallel / IEEE1284?

www.easysync.co.uk "sells a wide range single and multi-port RS232 / RS422 and RS485 converters at competitive prices"

Ethernet Terminal Server - eg Specialix. (MTC had a heap of old DECnet boxes)
 

These are components

Multicore shielded cable - 10 core low capacitance

25 pin D Male solder bucket
25 pin D Female solder bucket
Cover for 25 pin
9 pin D Male solder bucket
9 pin D Female solder bucket
Cover for 9 pin

16550A / 16550 / 16750 UART (not sure if its still made)
These are FIFO buffering UARTS useful for upgrading old machines to run Linux as a router.
 
 
 

Wireless transciever serial modules.

Circuit Design Inc make Audio - do they make serial