I don't understand how a 'set' is going to do anything for my data as it's just raw binary. It's created by ADC digitizing an analogue sonar echo with 10 or 12 bit resolution. The Teensy ADC routines for two channel operation returns a structure of two 16 bit integers, channel 1 and channel 2. I want to pass this back to the shore station in that form as a continuous byte sequence. I'll parse it into sonarArray[0..1, 0..1023] where the first index is the sonar pair, front/back and left/right pairs and the second is a time sequence in the echo. My command packet going out is also numeric as just three words, uint16_t. The meaning of the numbers will be handled at the receiving end with case/switch statements. I want to avoid any string data.
The transparent UART bridge looks like the best scheme as the three Teensies can listen and talk through the boat ESP and the laptop can do the same thing through it's FTDI USB/UART adapter and another ESP. I already have the serial link running using LazSerial/Synaser talking to my shore station Mega2560 at 2Mbps. I hope the ESP-Link library works with the Teensy. If not, then I can still use the Mega controller as it only runs as a UART to ESP interface and the TX burst generator. The real value of the Teensies will be on the boat with the faster dual channel ADCs.
I was not aware of the ESP-Link package. Thank you for that info. I had even considered using a video TX/RX pair at each end on different frequencies with the UART TTL as the signal. The problem with that scheme is the unknown coupling of the input to the FSK modulator, AC or DC.