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SATEL OY
// SATELLAR MANUAL // RADIO UNIT // USER GUIDE // V. 1.8
7. Settings
3
7.6 Packet mode radio access control
Packet mode radio access control is briefly explained in chapter 6.5.1.
Feature
Explanation
Sub unit
NMSID
Network topology *)
/ Handshake *)
FSK models (Network Topology)
Point to point
**
)
-mode: Recommended for the radio
networks where all the radio modems can reach each other and
the data collision avoidance is required to the radio interface.
Data retransmissions can be set ON/OFF at radio layer. With
RTS+CTS radio layer handshaking function.
0
1.430
Repeater
-mode: Recommended for the radio networks
where all the radio modems can’t reach each other directly.
Data retransmissions can be set ON/OFF at radio layer. With
RTS+CTS handshaking function. Longer CTS reply at the
receiving radio, which is received in hidden terminal cases
where part of the radio network can’t receive the original RTS
message.
Fast mode
–mode: only for radio networks with limited
amount of devices, where anti collision in the air interface
is taken into account in other part of the system. No data
retransmissions in the radio layer, no handshaking for the radio
layer.
Radio layer handshaking done always with 2FSK radio
modulation regardless of the user selected air rate. Radio layer
handshaking not displayed with TX/RX led indicators.
QAM models (Handshake)
HS OFF
–mode: Notification of transmission to begin. Radio
layer handshaking: CTSS > DATA > ACK (if Retransmissions
enabled in transmitting radio).
HS ON
–mode: Notification of the transmission to begin is
approved by the receiving radio layer handshaking: RTS -> CTS
-> DATA -> ACK (if Retransmissions enabled in transmitting
radio). RTS retransmissions always enabled. CTS message is
received also in other radio routers in the radio network for
”hidden terminal” cases, where part of the radio network can’t
receive the original RTS message.
Handshaking in the radio layer done always with selected QAM
modulation. Data retransmission in the radio layer possible
in both cases. Handshaking messages include the “channel
reserved” information. Radio layer handshaking displayed with
TX/RX led indicators.
