Hello,
The seller uses 'RS232' and 'TTL' interchangeably, not enough data is provided to determine if it's a drop-in replacement (the signalling voltages of RS232 can be triple+ that of TTL) If it's designed to interface directly to a microcontroller or Arduino using TTL, you'll probably need to use an external level shifter (such as an ICL3232 or MAX232) to use it on your Amiga's RS232 port
Also, as bbond007 mentioned, there's no flow-control capability so you'll only be able to use it asynchronously
