Title: Hardware Installation Guide.pdf
Field hardware products that are series 1 use 4-wire or 2-wire RS-485 full communication between devices. Only 2-wire RS-485 cable configuration can be used for series 2. The main run RS-485 cable used must be shielded, low capacitance, stranded, two twisted pairs with 100-ohm characteristic impedance or better (Belden 9842 4-wire or 9841, 2-wire, plenum cabling Belden 88102, or equivalent; refer to Cable Cross Reference Table on page 22). Wire size is 24 AWG minimum. Total length of the communication cable must not exceed 4000 feet (1219 m) for 24 AWG wire size per leg of the communication tree.Drops (down leads or stubs) to readers and other devices must be kept as short as possible (no longer than 10 feet). Use shielded 24 AWG cable (Belden 9502, or equivalent), when terminating to the 3-position for 2- wire RS-485 or the 5-position for 4-wire RS-485, insulation displacement connector.22 — revision 6Hardware Installation Guide1.5.2Use of Signal Ground (SG)