Function to calculate CRC16 (Modbus) value

There are a lot of resources online about the calculation of the crc16 for the modbus protocol.

For example:

http://www.ccontrolsys.com/w/How_to_Compute_the_Modbus_RTU_Message_CRC

http://www.modbustools.com/modbus_crc16.htm

I think that translating that code in c# should be simple.