Yes, I was referring to the Gateway sample code;
Serial.print(" - ACK...");
delay(3); //need this when sending right after reception .. ?
if (radio.sendWithRetry(theNodeID, "ACK TEST", cmdLen, 0)) // 0 = only 1 attempt, no retries
or any example where you need to transmit just after receiving....
BTW, what Felix refers as a library is not a library anyway....Library is a set of object code, and the "library" he refers is in source code (.cpp)
Thanks
Gus