Toshiba T300MVi - Manual (Page 21)

8
5. RS485 Port Electrical Interface
In order to ensure appropriate network conditions (signal voltage levels, etc.)
when using the interface’s RS485 port, some knowledge of the network
interface circuitry is required. Refer to Figure 1 for a simplified network
schematic of the RS485 interface circuitry. Note that the “Shield” terminal has
no internal connection: its purpose is simply to provide a cable shield chaining
location between devices. The shield is then typically connected to ground at
one location only.
Figure 1: RS485 Interface Circuitry Schematic
Figure 2 details the specific network connections to the RS485 terminal block
(TB1).
A
B
Signal Ground
Shield
Figure 2: RS485 Terminal Block (TB1) Connections