USB (J4)

Parameter

Value

Connector

USB 2.0 type B, on the front panel

Speed

Full speed (12 Mbit/s)

Class

HID — no driver installation is required

Protection

ESD array on D+/D−; VBUS fused at 0.25 A and clamped

Bus power

Not used. The board does not draw operating power from USB and does not run with USB alone

RS-485 (J2)

Parameter

Value

Connector

3-way pluggable terminal block, 3.81 mm, marked + − G

Signalling

Half duplex, 2-wire, referenced to logic ground

Baud rates

9600 to 115200

Termination

120 Ω fitted on the board, permanently connected across the pair

Protection

Bidirectional TVS across the pair plus an ESD array to ground; 10 Ω series resistors

Termination. The 120 Ω terminator is always present and cannot be removed without reworking the board. On a multi-drop RS-485 segment this unit must therefore be placed at one end of the line. Do not fit additional termination at the same end.