9.2.2.1 Data Rate and Bus Length

The RS-485 standard has typical curves similar to those shown in Figure 33. These curves show the inverse relationship between signaling rate and cable length. If the data rate of the payload between two nodes is lower, the cable length between the nodes can be longer.

Figure 33. Cable Length vs Data Rate Characteristics

Applications can increase the cable length at slower data rates compared to what is shown in Figure 33 by allowing for jitter of 5% or higher. Use Figure 33 as a guideline for cable selection, data rate, cable length and subsequent jitter budgeting.