Like many people over 55, I decided to move to a senior development, even though I did know that there were many restrictions for hams. After some time I found out about digital modes and that they did not create radio interference.
I then checked out PSK31 as a good operating mode. In talking with several ham friends, one sent me a simple circuit for an interface between the PC and a rig. After checking the circuit I went to my electronic parts and found most of the isolation transformers and the opto isolator chip. Since I like building circuits, I put the interface together and am in the process of hooking it up to the PC and the rig.
If you need any parts to build up this unit check with Mouser Electronics for the 600 ohm isolation transformers Part number LM-NP-1001-B1L and the 4N35 opto isolator chip 526-NTE 3083 these are the major parts for the interface unit. Below is a copy of the circuit and pictures. See you on PSK31.