User's Manual

S2510 Reader - Reference Guide April ’00

3.2.5 Master/Slave Synchronization

Master/Slave Synchronization is probably the most commonly used form of synchro-

nization. One reader is configured to be the

Master

and this reader then controls all

the other readers, which are configured as

Slaves

There are three variants:

Master/Slave Synchronization without Acknowledgement,

Master/Slave Synchronization with Acknowledgement

Triggered Synchronization.

3.2.5.1 M/S Synchronization without Acknowledgement.

This method of synchronization is the fastest method of reading transponders and

was originally developed for reading tagged vehicles at speed. It assumes that all

readers are on the same synchronization bus and the readers would not, for exam-

ple, recognise a handheld reader that is trying (probably unsuccessfully) to perform

a reading.

Advantages:

1. Uses a single twisted pair cable.

2. Has the fastest read rate.

3. The Master can be used for Charge-only read or Write/Program.

Disadvantages:

1. All readers must be on the same synchronization bus.

2. If the Master fails, all units stop.

3. Slave units cannot be individually tested without the Master running.

4. Slaves must perform exactly the same RF-Task as the Master (read the

same page, write the same data to a transponder).

3.2.5.2 M/S Synchronization with Acknowledgement.

In Master/Slave Synchronization without acknowledgement, if a slave reads a trans-

ponder and the master doesn’t, the slave may miss the next pulse while it is process-

ing the reading from that transponder. In Master/Slave with Acknowledgement the

Master has to wait until all slaves have completed their current cycle before initiating

the next cycle. This is achieved by using a 4 wire synchronization bus (twin twisted

pair) with the slave transmit lines coupled back to the Master receive lines.

This method has the following advantages over Master/Slave without Acknowledge

1. All units can Write/Program transponders (providing they do it together).

2. They wait for the slowest to complete.

Disadvantages:

1. The cable is a twin twisted pair.

2. The readers cannot be too close if writing is performed, because of the pos-

sibility of corrupted data. This restriction also includes the paged read of

multipage transponders.