Operations and Maintenance Manual

MPR 4.1

Reader Maintenance Instructions

Confidential UM UM360479-100 Revision: Draft B4 Page 77 of 246

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FILE: UM360479-100 REV B4 DRAFT WIP MPR-4.1 READER OPERATIONS AND MAINTENANCE MANUAL (002).DOCX

05/25/2022 11:18

Kapsch TrafficCom

slot 1. This can be seen in the truth table shown below for synchronization circuit consisting of two

Readers.

Table 4-1: Boolean Logic Truth Table for Synchronization of two Readers

The truth table above demonstrates the following rule of synchronization operation:

• The sync bus will only be in the ready state when all Readers in the group are in the ready

state.

The last Reader to acquire a ready state controls the system synchronization. Most of the time

(greater than 95%), the sync bus will be in the busy state. If operating correctly, the sync bus will

normally be in the ready state for about 100 sec.

Transaction Buffering

Transactions from OBUs, are processed by the Reader. When a Reader loses communications with a

Lane Controller (LC), the Reader buffers OBU transactions and error messages (up to a combined total

of 1,000,000) in non-volatile memory (i.e., buffered messages will not be lost during power

interruptions or Reader resets). When the memory is full, new transactions overwrite the oldest

buffered transactions. The memory available for buffering is shared by all RF Ports.

When the communication link between an LC and the Reader is re-established, the Reader begins to

upload the buffered transactions to the LC. The Reader will pause uploading buffered transactions to

the LC to report any new transactions as they occur. Buffered transaction reporting resumes after the

new transactions have been reported. Messages from the LC will continue to be acknowledged and

acted upon during the upload process.

Reader 1 sync port Tx

Reader 2 sync port Tx

Reader 1 or 2 sync port Rx

0 (ready)

1 (busy)

0 (ready)

1 (busy)