RS485 termination / bias adapter

USB-485

I have been testing some RS485 communications of recent, and found the need for some flexible adapters for the above interface box. The adapters are to provide selectable line termination and fail-safe bias.

Krone LSA

RS485Adapter00

Above is one of the adapters with a 3 way Krone LSA terminal set for the line. The left hand shunt selects line termination (120Ω), and the right hand pair select fail-safe bias (2 x 470Ω). Test points provide convenient attachment of a scope.

The adapter has a short tail to a 8 way plug to suit the USB adapter.

RS485Adapter01

Above is the underside.

Pluggable 5.08mm pitch header

RS485Adapter10

Above is one of the adapters with a 3 way pluggable header for the line. The left hand shunt selects line termination (120Ω), and the right hand pair select fail-safe bias (2 x 470Ω). Test points provide convenient attachment of a scope.

The adapter has a short tail to a 8 way plug to suit the USB adapter.

RS485Adapter11

Above is the underside.

The layouts are very similar, but the tracks are displaced by one track in the two adapters to suit the connector pins.