I would like to get some clarification on: 1) the maximum request packet size 2) the maximum response packet size
The HDLC layer to the device has a message size of 512, leaving a maximum of payload of 512 - 7 (HDLC header size).
However, if I attempt to send a 286 byte request to the end point I get a 4.13 response i.e. request entity too large. 158 byte requests work. So what is the actual limit for a request (presumably somewhere between 158 and 286)?