TransCore 05716 Manuel D’Utilisation
Multiprotocol Rail Reader System Guide
6-10
ECP host transmission
#7647XXX<crc><eom>
where
#
Start-of-message character
7
Message sequence number
647XXX
Select RF Operating Frequency
command where
647XXX is the command and XXX is a hexadecimal value from
000 to 118. In this example, XXX sets the RF frequency to 903
MHz.
000 to 118. In this example, XXX sets the RF frequency to 903
MHz.
<crc>
CRC
value for the message
<eom>
End-of-message character
Done
Command has been invoked by the MPRR
Reader response
#7Done<crc><eom> or #7Error<eom>
For some commands, the MPRR responds with data that relates to the command, such
as T0F 0, to indicate (TBD) mode enabled for a #XXX Display (TBD) Mode Status
command.
as T0F 0, to indicate (TBD) mode enabled for a #XXX Display (TBD) Mode Status
command.
#7Error<eom>
will be returned if host transmission is not a legal command with
legal data.
Timing and Synchronization
The ECP is largely independent of baud rate. The timeout delays previously described
are a function of baud rate.
are a function of baud rate.
The MPRR supports an ECP timeout, which applies equally to both transmit and
receive.
receive.
The receiver’s minimum timeout delay equals the time to transmit/receive the longest
anticipated message at the current baud rate setting. Additional margin should be
included for idle periods between characters; for example, processing overhead, if
any. The timeout delay period can be expressed as follows:
anticipated message at the current baud rate setting. Additional margin should be
included for idle periods between characters; for example, processing overhead, if
any. The timeout delay period can be expressed as follows:
Τ
rec
(ms) = L x [
Τ
char
+
Τ
idle
]
where
Τ
char
(ms)
1000 x [ B
c
/ R
b
]
B
c
Bits per character, typically 10