Hach LOC 100 Manuel D'utilisation page 72

Note: One long tone indicates that the tag has been read or written
successfully. An error, e. g. because the distance from the tag is too
great, is indicated by five short tones and an error message.
English 72
Figure 4 Read and write data using the LOC 100
1. Left key (Read)
2. Right key (Write)
3. Operator RFID tag or location RFID tag