SATELLINE-EASy / SATELLINE-EASy 869
User Guide, Version 3.0
22
4.6.1
CTS line
•
CTS (Clear To Send) is a signal from the radio modem to the DTE. It indicates when the
radio modem is ready to accept more data from the DTE. The options for CTS line are:
•
Clear To Send - CTS line is set active when the radio modem is ready to accept data for
transmission. CTS will shift into inactive state during data reception, and at the end of
transmission. CTS shifts back into active state either when reception ends or the radio
modem has finished data transmission. CTS will also shift into inactive state when the
transmit buffer is about to overflow i.e. there is more data coming in from the serial port
than the radio is able to transmit.
•
TX buffer state - CTS will shift into inactive state only if the radio modem’s TX buffer is
about to overflow. This typically happens when the transfer speed on the serial interface
is greater than on the radio interface, and the size of transmitted messages is large.
4.6.2
CD line
CD (Carrier Detect) is a signal from the radio modem to the DTE. It indicates when there is
activity on the radio channel. The options for CD line are:
•
RSSI-threshold - CD is active whenever a signal exceeding the level required for reception
exists on the radio channel. It doesn’t make any difference if the signal is an actual data
transmission, a signal of a radio transmitter not belonging to the system, or even an
interference signal. CD is also active when the radio modem itself is transmitting.
•
Data on channel - CD will switch to active state only after recognition of a valid data
transmission. CD will not react to interference signals or noise.
•
Always ON - CD is always in the active state. This option can be used with terminal
equipment that treats CD line as an indicator of an active connection.
•
Ext Antenna Control – CD follows the status of the transmitter. This option can be used
for controlling external equipment e.g. antenna switches.
4.6.3
RTS line
The options for RTS-line are:
•
Ignored - RTS-line status is ignored.
•
Flow control - The radio modem transmits data to the terminal device only when the RTS-
line is active. Non-active state of the RTS-line will force the radio modem to buffer the
received data. This option is used if the terminal device is too slow to handle data
received from the radio modem.
