My application uses two softwareSerial ports. One to talk to the ESP8266 at 9600bps and another to talk to another device at 1200bps. The latter doesn’t support higher speeds. In most cases the application replicates data packets from one to port to the other with or without pre-processing.
My question is how to avoid overflow situations in the slower serial port considering that there is no serial buffer on Tx. In other words, how can I make sure that one packet has been completely sent before trying to send the next?