: These involve fixed or auto-baud rate switching for simple data transmissions.
: The most advanced mode, which allows for the use of other protocols (like DLMS/COSEM) to be tunneled through the IEC 62056-21 connection for high-level security and complex data structures. The Role of ASCII and Readability
: Specifically for data transmission at a fixed 2400 baud rate.
: If remote communication fails, the physical port defined by this standard provides a "fail-safe" way to retrieve billing data. Conclusion