ProSoft Technology RLX-IFH9E-A - Manual (Page 61)

RLX-IFHE ♦ RadioLinx Industrial Wireless Installing the Radios
RadioLinx® Industrial Frequency Hopping Ethernet Radios User Manual
ProSoft Technology, Inc. Page 61 of 109
November 19, 2013
Pin Name Pin Number
DB9 / DB25 Function
Signal Ground (SG) Pin 5 / 7 Signal ground
Communication signals diminish in strength as they travel through cable. The
maximum cable lengths for RS-232 are less than RS-485 because the RS-232
interface is more susceptible to noise. The data performance of RS-232 and RS-
485 is similar as long as the cable requirements are met. The following table
gives an estimation of the cable length requirements for the two serial interface
protocols:
Characteristic RS-232 RS-485
Maximum cable length 100 feet 4000 feet
Maximum bits/sec. 20kbps 100Mbps
There are different ways to transfer data serially; simplex, half-duplex, and full-
duplex. Simplex communication mode allows transmission of data in one
direction only. In the half-duplex mode, data can be transferred in both
directions, but not simultaneously. That means data can be transferred over a
single pair of wires, but the data can only be transferred in one direction at a
time. Full-duplex mode utilizes two pairs of wires and the data can be
transferred in both directions simultaneously.
Radio RS-485 Cable Specification