interface IrDA with encoder

Question

We have a pair of IrDA and its encoder/decoder. After reading the datasheet, we still dont know how to interface IrDA with En/Decoder.
Here is our current connection:

When using BAUD rate 9600, we are not getting any readable data from UART on arduino. The buffer is alway full or 0. We don't know whether it's the en/decoder or IrDA transceiver that is causing the problem.
Is this the right way to interface? Any advice on how to go about debugging this?

Related datasheet and info
IrDA Vishay TFDT4500 : http://www.freeweb.hu/bat21/irda/tfd_4.pdf
En/Decoder MCP2120 : http://ww1.microchip.com/downloads/en/DeviceDoc/21618b.pdf

Answer 1

To trouble shoot i would hook up the TXIR RXIR(mcp2120) pins together and make a loop back device. Just to make sure your encoder/decoder works, what you send to the Chip should be echoed back to the uC. Once you confirm that the TX RX lines are working, you would then test to see if your IR sensors are transmitting and receiving by using a digital camera or webcam. The other way to debug this is if you have an oscilloscope on hand to check the data lines.

all your connections and pins do look correct, and your clock source is correct for your baud pins for 9600