Manufacturing of RS-422
Belden makes an entire line of RS-422 cables. See part numbers 9804-9825, 9829-9838, 8102-8125, 9729-9738, 8162-8185, and 1419A-1425A.Plenum RS-422
Belden makes Plenum RS-422. See part numbers 88102-88125 and 89729-89758.Run Length for RS-422
Maximum permissible length is a function of several variables including data rate and noise. The appendix of the RS-422 standard contains application guidelines including information related to cable length.