I worked to get the Linux kernel driver to work at arbitrary baud rates on the Prolific PL2303A-TA USB to serial chip.

This can do 5 bit / 1.5 stop / 45 baud with the linux driver although the chip can actually get closer to 45.45 Bd if you want to tweak the driver. (the linux ioctl call (termios2 structure) only handles integer bit rates)

This chip is used in this USB to serial device (and many others) https://www.amazon.com/Sabrent-Converter-Prolific-Chipset-CB-DB9P/dp/B00IDSM6BW

 

I was using it with the ASR33 (110 Bd) but did check the 45 Bd use. As with the 33 you will need to go from RS232 to current loop.

Michael   NV3Z / VK2BEA / G4NYV