User manual

Table Of Contents
IMPORTANT
When data transmission is complete, the SIM must be powered off before the next tone detect is
sent; otherwise, both the surface modem and the inductive modem will be in ‘listening mode’
simultaneously and cannot perform the communication sequence.
Transmission Communication Sequence – Technical Details
The next section describes technical details of the communication sequence including
command and transmission sequences, data formats and file transmission protocols.
Command Sequences
At the completion of a profile, the MMP powers on the UIM and begins a transmission
session by listening for one of the following command sequences: REQNEW, REQDIR,
REQFIL, REQEOD. Each command sequence is described below.
Command Sequence Action
REQNEW MMP sends the next file in the list of files
collected since the last successful
transmission.
REQFIL filename.ext MMP sends the requested file.
REQDIR MMP sends a full listing of all files on the
flash card.
REQEOD MMP powers off the UIM.
REQACK (sent as a binary command) The MMP interprets this command as an
acknowledgement that the last data packet
sent was received successfully. The MMP
will transmit the next data packet.
REQNAK (sent as a binary command) The MMP interprets this command as a
failure for the last data packet sent. The
MMP will resend the data packet.
Appendix J-2