AX.25 encode is complete and seems to work well. AX.25 decode works, but I have a special mode and also have a CTCSS listen setup to remotely turn on that mode. Still some items to do , but its almost time to put this on a board. If you are interested in this project please let me know. I was able to get my Brother Laser printer to work with the toner transfer method after some trial and error. I had great results using a Brother HL-4070CDW and Kodak inkjet photo paper using a iron and being very patient with the soak.
I experimented with several designs. A resistor ladder, a CML modem IC, and a DAC. They all seem to work but my goal would be to have a nice small unit I can carry around that does double duty as a simple repeater controller. So far so good. I went back and used both a DAC and a AKM CTCSS chip to do what i needed for dual duty. I plan on building a version on a pcb with the CML but I want to try the newer 800 series as its pretty much an all in one device.