Your summary is correct. The module can’t receive another packet if it is not in IDLE. If a new packet is transmitting from the meter while the Master is occupied sending last received packet out on UART, the new packet will not be received. Increasing the UART baud rate to max will mimimize the likelihood of this incident.
Last Update: October 9, 2017
October 9, 2017 1590 Wireless M-Bus Q&A