There are three type of packets available on the SPIRIT1: stack, wireless M-Bus, and basic. Other features that the SPIRIT1 data link offers are: automatic acknowledge, after receiving a message the receiver SPIRIT1 will automatically send and acknowledge back to the transmitter (without any microcontroller intervention); retransmission, it is possible to program the transmitter SPIRIT1 in order to have automatic retransmissions if it does not receive any ACK after a message transmission within a programmed time; automatic address recognition, it is also possible to have automatic address recognition and packet filtering to verify that the receiver SPIRIT1 is receiving the information from the proper transmitter; and TX/RX FIFO, SPIRIT1 also features a 96 byte FIFO for transmission and reception, acting like a small cache and helping the communication.