the transceiver 10 the message from the master is sent on the link 4 and temporarily stored in the message store 11 in the message store any commands for the transceiver are extracted and sent to the command interpreter 12 if the command interpreter 12 is locked then the command is not executed the command interpreter can then send back an error message to the controller which will tell it that the command failed if it is unlocked the command is executed the command interpreter itself can detect that a command has been received and warn the local device using a more complex command interpreter such a warning can be used for the unlocking protocol the lock 15 is used as a security feature so that it will be impossible to remotely write to any registers in the receiver without first getting permission to do so this permission is given by the local application the remote application may send a request that is interpreted in the local application the local application may then grant or deny writing to registers in the local receiver when the remote command has been performed the lock in the receiver may be automatically set again so that no further writing to the registers is permitted until a new authorization is received fig3 shows the command interpreter in more detail this consists of a decoder 10.