I came across these tools from a past life/job. How many can you identify?  25 to 25 pin M/F serial straight-through cable, 9 pin break-out cable, 9 to 25 pin adapter, cable stripper, modem cable, DIP extractor, phone polarity tester, phone splitter, DIP inserter, break-out box,  grounding wrist strap, punch-down tool, DIP pin straightener, Modem.

Extra credit

What is the purpose of the 9-volt battery?
What is the distinctive yellow cable?