interconnected via wiring conductors the conductors leading from one instrument such as the controller 370 shown in fig3 c must lead to a particular input of a second instrument downhole tools such as the prior art described above typically include instruments disposed in two pipe joints are interconnected via a single conductor leading from the first instrument in an uphole pipe joint to a single ring connector contact a corresponding single ring connector contact in the downhole pipe joint mates with the contact in the uphole ring connector and a conductor leads from the downhole ring connector to an instrument disposed in the downhole pipe joint a major advantage of the present invention is realized when as shown in fig3 c a downhole pipe joint 356 includes an instrument 374 requiring multiple input wires 376 the instrument shown is disposed in the downhole pipe joint 356 multiple wires 376 lead from the instrument 374 to corresponding multiple contacts 378 of which only one is shown when the uphole pipe 352 is coupled to the downhole pipe 356 the contacts 364 in the uphole pipe 352 interface with the contacts 378 disposed in the downhole pipe 356 the esu 368 includes a measuring device 380 such as an ohm current or voltage.