H1 is ethernet with an additional application layer called TF (Technical Functions). This allows equipment to talk to each other more efficiently thus improving performance. I believe that the association layer is layer 7 in the ethernet spec. Hope this helps.
H1 was the former name given by SIEMENS to their Ethernet based PLC communication. It is now called 'Industrial Ethernet'. The name 'H1' relates to the physical (ethernet) as well as the protocol layer. There are two flavors, one for low-level access with some protocol on OSI transport layer (COTP TP4). The protocol is decribed in the manuals for the S5 comm. processor board and is often called 'H1 protocol'. Then there is a more sophisticated protocol TF, which handles typified data. The philosophy is very similar to MAP/MMS. There is also now a TCP/IP-based version, which uses RFC1006.