If you're running code in the NetLinx master to parse strings from the TPControl device, the NetLinx masters, is that devices will not parse strings unless they are told to by the NetLinx master. When you code for return buffers for RS232 ports, Touch Panels etc (e.g. data_event[] { string: { } } or create_buffer) then the NetLinx master automatically issues an RXON command to respective devices. The RXON command basically gives the device permission to send strings. So, AMX manages to flow with use of the RXON/RXOFF commands.

So, if you simply add "data_event[] { string: { } }" or "create_buffer ,[buffer]" to your code, and then watch via 'NetLinx Studio -> Diagnostics -> Notifications' with 'cmd to' enabled for all devices, you will see the RXON command get issued automatically. Then, you will be able to see any strings issued back from the device.