Advertisement
1
The MLU does not regard a carrier signal on the line (indicated by the DCD signal from
the modem) as an incoming seizure.
Bit 2 (speed switching call dependent):
This bit indicates if the transmission speed of the modem can be switched between high-speed
and low-speed. This switching can be invoked by setting the Data Signal Rate Selector (CT111)
signal to the modem to true or false. This signal can be set true or false per call (speed
switching call dependent) or fixed to the set or the reset value (speed fixed to high-speed or
low-speed).
0
The switching between low-speed and high-speed is not possible per call. The speed of
the call must now be fixed to the high-speed or the low-speed (see bit 3).
1
The switching between low-speed and high-speed is possible per call. Every call holds
additional information which contains the speed. If the speed of the call is smaller than
the projected byte 0 (see later on) the low-speed is used.
If the speed of the call is higher than the projected byte 0 the high-speed is used.
Bit 3 (speed fixed to high-speed):
This bit indicates if the transmission speed of the modem is fixed to high-speed or fixed to low-
speed. This bit is used both for leased lines and when the modem is used as convertor.
In case of a convertor this bit is only used when bit 2 is 0.
0
The speed is fixed to low-speed by means of a constant value of the signal DSRS
(CT111).
1
The speed is fixed to high-speed by means of a constant value of the signal DSRS
(CT111).
Bit 4 (constant carrier with guarding):
This bit indicates if the MLU must be blocked if no carrier is detected on the leased line.
The MLU expects a constant carrier on the line according to bit 1.
0
The service condition of the MLU-circuit is not changed when the DCD signal (CT109)
of the modem is reset. The line is not guarded.
1
The service condition of the MLU-circuit is changed to ABL-FAIL when the DCD signal
(CT109) of the modem is reset. The line is considered out of order.
Bit 5 (direction call dependent):
This bit indicates if the MLU is able to set the modem in the calling or in the answering mode
by signal Select Transmit Frequency (CT126). If the modem is in the calling modem, the low
frequency band is used to send information and the high frequency band is used to receive
information. If the modem is in the answering mode the frequency bands are reversed.
0
The MLU-circuit is not able to force the modem in the calling or answering mode and
the direction must be fixed to incoming or outgoing (see bit 6).
1
The MLU-circuit is able to force the modem in the calling or answering condition by
CT126. The MLU-circuit must be assigned a line number in a bundle with the direction
bothway.
Bit 6 (direction fixed):
only used when modem used as convertor
only used with leased lines & constant carrier
only used with leased lines
only used with leased lines
85
Advertisement
