LRS400S Data Transceiver Users Manual
LUM0025AA Rev A
Version 1.0
19
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S
LAVE
S
ECURITY
Slave security is a feature which 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 Masters 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.
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RTS
TO
CTS
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. At the minimum settings for Max and Min
Packet Size (0), the time will be approximately 5.9 ms. Please note that this latency can increase
significantly if packets are lost between the Master and Slave. In Point-to-MultiPoint mode, there is no
absolute guarantee that the state change will be communicated to all Slaves in the unlikely event that all
repeated packets from the Master do not get through to all Slaves.
Note:
If DTRConnect is enabled and set to 2, the RTS to CTS feature will not work.
Note:
If the DTRConnect is enabled and set to 1, RTS to CTS mode takes precedence over the
functionality of the CTS line on the Slave relating to the DTRConnect feature.
Note:
The RTS to CTS option is only available in RS232 mode.
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R
ETRY
T
IME
O
UT
The Retry Time Out parameter in a Slave sets the delay the unit will wait before dropping the connection
to a Master in MultiPoint mode. The factory default is set at the maximum of 255. The maximum setting
means that if 1 packet in 255 is sent successfully from the Master to the Slave, the link will be maintained.
The minimum setting is 8. This allows a Slave to drop a connection if less than 1 in 8 consecutive packets
is successfully received from the Master.
