<font color='#000000'>I can think of 2 things to check. First, check the setup on your dvd/cd player to be sure that digital output is enabled.I dont know what kind of unit you have & most of them will have it set already, all you should do is verify that it is not optioned for "PCM" only, but "stream/PCM" or "dolby/PCM".
I have a Yamaha receiver but am not familiar with the back of the 1200 that you have. There is an option to cross-connect the digital inputs to the particular piece of equip. you wish to use. From the factory the inputs are pre-assigned in the unit & its possible that the dig. coax input is assigned to another piece of equip. on your remote.
The easiest way to check this is to pop a cd in & then go through all the input options with the remote(dvd,vcr,satt,cbl,etc.) until you hear sound. When you have ID'ed which option is giving you sound you can go into the recvrs setup menu ( I highly suggest using the manual for this) & reassign the dig. coax input to the option you would like it to work with.
If none of this works you may have a bad coax &, if you have a spare, may want to eliminate this possibility 1st.</font>