Skip to content

Boltek EFA-21 Power Module / RS485 to USB Converter for EFM-100C

The EFA-21 is designed to provide both power and data through a single Cat5 cable which eliminates the need for the additional fiber optic cable so that only a single Cat5 cable is connected from the EFM-100 to the adapter to provide both power and data.

The RS-485 output on the EFA-21 can also feed into the ERL-10 when the input jumpers are set to RS-485 (see jumper settings in ERL-10 manual)

The EFA-21 RS485 to USB output is designed to work mainy with the EFM-100C and EFM-485 models. It can be used as a power source for the EFM-100A model, and provide analog output on the terminal block but does not does not provide any data output on the USB port. It is recommended that the EPM-1 and EFA-10/EFA-20 are still used with the EFM-100A.


EFA-21 Adapter Device Drivers

Shipping is fast and FREE across the USA for all orders $199 or more. For more details about shipping see the full shipping page here.

We offer 30 Day Easy Returns. If you decide you don't need a product we'll take it back so long as it is in original and re-saleable condition. See the full details here.

Found a better price online? We'll match it or beat it if we can. 

All you need to do is let us know via phone or email ( and we'll let you know what we can do.

You will need to provide evidence of the better price online and it must include any shipping or taxes charged by that site. i.e. It needs to be the total price.

This only applies to new products, it does not apply to used condition products.