FreeWave Technologies Inc. 1521131FFF Manuale Utente

 Spread Spectrum Wireless Data Transceiver User Manual 

LUM0002AG Rev A 

Version 7.0 

35 

Note:   The FGR2 has an added RF setting of 1. This allows the RF Data Rate to be increased to 

230.4kbps. As with all FreeWave networks the RF Data rate MUST be the same throughout the 
network.  A new network of only FGR2 transceivers may be set to run at the faster data rate of 1. 
However, if even 1 DGR or FGR transceiver is introduced into the network that site will not 
function at the higher speed. The Data Rates of 2 and 3 are fully supported by the FGR2. 

For more information, refer to the Installation Guides for the 900 MHz and 2.4 GHz wireless modems. 
 

Slave security is a feature that allows Slave transceivers to accept transmissions from a Master not 
included in the Call Book. The default setting is 0 (Slave Security enabled) which means, only a Master 
which is in the Slaves’ Call Book may link to that Slave.   

Slave Security may be disabled (setting of 1) allowing any Master to call the Slave. Slave Security has no 
effect in Point-to-MultiPoint networks where the Network ID is not set to 255.   

Slave Security must be set to 1 when the unit is operating in Mode 6 Slave/Master switchable or a Point-
to-Point network where the Slave may need to accept calls from more than 10 different Masters. When 
Slave Security is set to 1, the transceiver will accept calls from any other FreeWave transceiver. 
Additional network security measures may be taken to prevent unauthorized access, such as changing 
default settings for FreqKey, Hop Table or Frequency Zones.  

Menu selection RTS to CTS in the Radio Parameters menu provides the option of allowing the RTS line 
on the Master transceiver to control the CTS line of the Slave. This pass-through control can be enabled 
in both Point-to-Point and Point-to-MultiPoint. In MultiPoint networks, the Master RTS line will control all 
Slaves’ CTS lines. When enabled, the CTS line ceases to function as flow control. It is not recommended 
to enable this feature when operating at RS-232 speeds above 38.4kB. 

The default setting of 0 disables this function, where as a setting of 1 enables RTS-CTS control.   

RTS-CTS setting 2 is described in detail in the application note #5437 DTR to CTS Line Alarm Feature.  

With an RTS to CTS setting of 1, the Master senses the RTS line prior to all scheduled packet 
transmissions.  If the state has changed, the Master will then transmit a message to the Slave with the 
new status. This transmission will occur regardless of data being sent.  If data is ready to be sent, the 
RTS status message will be sent in addition to the data.  In Point-to-Point mode, the Master will continue 
sending the new status message until it receives an acknowledgment from the Slave. In MultiPoint mode, 
the Master will repeat the message the number of times equal to the Master Packet Repeat value in the 
MultiPoint Parameters menu.  

Master transmit times are completely asynchronous to the occurrence of any change of the RTS line; the 
latency time from RTS to CTS is variable.  The Max and Min Packet Size parameters in the Radio 
Parameter menu determine this duration.  Setting both parameters to their maximum value of 9 will 
produce a maximum latency time of approximately 21 ms, given no Repeaters in the network. At the 
minimum settings for Max and Min Packet Size (0), the time will be approximately 5.9ms. Please note that 
this latency can increase significantly if packets are lost between the Master and Slave. In Point-to-
MultiPoint mode, no absolute guarantee is made that the state change will be communicated to all 
Slaves.  In Multipoint networks with Repeaters present, the latency will be cumulative for each serial 
Repeater.  

For example: If the latency between the Master and the first Repeater is 15 ms, and 2 serial Repeaters 
are present, the total latency will be 45 ms. (M—R1 (15 ms) + R1—R2 (15 ms) + R2—S (15 ms) = 45 ms)