User's Manual

FreeWave Technologies Spread Spectrum Transceiver User Manual

900 MHz and 2.4 GHz

V5.0S

(6) NetWork ID

Option (6) NetWork ID allows multipoint networks to be established without the

use of the Call Book. If the NetWork ID is set to any value other than the default

(255) and no higher than 4095 the slaves in the multipoint network will

communicate with the first multipoint master or repeater heard with the same

NetWork ID. When the NetWork ID is used multipoint masters and repeaters may

be replaced without reprogramming all of the slaves in the network. In addition,

this allows a slave to establish communications with different Masters (though not

at the same time) without having the serial numbers in the Call Book. This is very

useful in mobile multipoint applications.

(8) MultiMaster Synch

(8) MultiMaster Synch is reserved for applications (either point to point or

multipoint) with concentrations of Master units where it is necessary to reduce

interference between the Masters. Please contact FreeWave Technologies for

more information.

(9) 1 PPS Enable/Delay

The 1 PPS Enable/Delay option allows the radio network to propagate a GPS

1PPS signal from the master transceiver to all slaves in a multipoint network.

When this parameter is properly enabled a 1 PPS pulse on the DTR pin of the

master will provide a 1 PPS pulse on the CD line of any slave in the network.

To use the 1 PPS Enable/Delay feature the steps outlined below must be followed:

1. The 1 PPS Enable/Delay parameter in the master must be set to 0.

2. The master must have a 1 PPS pulse on the DTR pin.

3. The 1 PPS Enable/Delay parameter on the slaves must be enabled. The

calibration on the slave is typically factory set. However, the slaves may

also be calibrated with the following procedures:

1. Trigger an oscilloscope on the 1 PPS pulse (from a GPS

receiver) on the DTR pin of the master.

2. Monitor the CD line of the slave.

3. If the timing on the slave differs from the master it may be

adjusted via the value in the slave's 1 PPS Enable/Delay

parameter. The difference in time between each incremental

integer value is 542.534nS. Changing the parameter to higher

values decreases the slave time delay and changing the

parameter to lower values increases the time delay.

When properly calibrated the CD line of a slave radio will output a pulse that goes

high for about 2 mS in synch with the 1 PPS pulse on the master radio. The

output on the slave will occur within 20 microseconds of the input to the master.

Note: When 1 PPS is enabled the master must have a 1 PPS pulse on its DTR

pin, otherwise the network will not function.