SATEL-EASy+
User guide
Version 1.33
28
5.6.3 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.
5.6.4 DTR line
DTR (Data Terminal Ready) has a special function in the radio modem - it can be used as an
external ON/OFF switch for power saving purposes. When DTR-signal is LOW radio modem goes
to low power saving mode where none of its functions are operational. When DTR signal is
pulled HIGH radio modem will start up. During low power mode radio modem is reset.
If the DTR pin is not connected i.e. floating, the radio modem is ON by default.
5.6.5 DSR line
DSR (Data Set Ready) is a signal from the radio modem to the DTE. It indicates that the radio
modem is powered up.
5.7 Pause length
The modem recognises a pause on the serial line (a pause is defined as a time with no status
changes on the RS-232 interface TD-line). The pause detection is used as criteria for:
• End of radio transmission - When the transmit buffer is empty and a pause is detected,
the modem stops the transmission and will then change the radio to the receive mode.
• SL command recognition - For a SL command to be valid, a pause must be detected
before the actual command character string.
• User address recognition - In order for the start character to be detected, a pause must
precede it in transmission.
Traditionally, in asynchronous data communication, pauses have been used to separate serial
messages from each other. However, the use of non-real-time operating systems (frequently
used on PC-type hardware) often adds random pauses, which may result in the user data
splitting into two or more separate radio transmissions. This may cause problems especially in
the systems including repeater stations.
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