RS485 read data from fingerprint slave device

[tozoysa]

Hello,

I have purchased a fingerprint slave module thinking that i could read the output of the module and process it by myself via a microcontroller. The module i purchased has only RS485 interface. Wonder if i could read the output using RS485 to TTL convertor(Maybe using arduino serial monitor, or teraterm perhaps?) using this module?

Fingerprint slave module : https://www.alibaba.com/product-detail/HF-F12-Fingerprint-and-ID-Card_60355134367.html
RS485 to TTL convertor : http://www.ebay.com/itm/272351498314?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT - I'm still waiting for this to arrive though 

Please advice!

Thanks in advance!

Regards,
Prasad.

[ajb]

That will probably work, as long as the reader only uses a single half-duplex pair.  If it uses separate Rx/Tx pairs you'll need a second transceiver.  RS485 is just an electrical specification, though, so you'll need to know what sort of data format the reader uses.  It's probably a simple UART protocol, but at the very least you'll need to find out what baud rate, parity type, and number of stop bits the reader uses.  Beyond that, you'll need to know how the data is structured and transmitted, which can vary quite widely.

[mikeselectricstuff]

If it uses separate Rx/Tx pairs

That would be RS422

[ajb]

If it uses separate Rx/Tx pairs

That would be RS422

Yes, but I wouldn't be too quick to trust most non-specialist vendors to make that distinction, let alone some random alibaba seller...

[CM800]

If it uses separate Rx/Tx pairs

That would be RS422

Yes, but I wouldn't be too quick to trust most non-specialist vendors to make that distinction, let alone some random alibaba seller...

Yes, I will say RS422 / RS-485 is used pretty interchangeably, even in the motion control industry. I've been prodding various suppliers to correct it for some time!