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ISDN TA/V
14.5.1 DTR C
ONTROL
Data Terminal Ready is the signaling circuit used to indicate to the ISDN
TA/V when the attached computer/terminal is able to send or receive
information. Whenever DTR is present on the DTE interface this is indicated
by your ISDN TA/V’s
TERMINAL
LED being lit.
How this signal is treated by the ISDN TA/V is determined by the
&D
command.
&D0
ISDN TA/V ignores the true status of DTR and treats it
as always ON.
&D2
User controlled signalling. DTR is controlled by the DTE.
14.5.2 DSR C
ONTROL
Data Set Ready is the signaling circuit used to indicate to the attached
computer/terminal that the ISDN TA/V is ready to send information to the
DTE. How this signal is treated by the ISDN TA/V is determined by the
&S
command.
&S0
DSR is forced on at all times.
&S1
Normal RS-232 signaling is respected. DSR is controlled by
the DCE.
&S2
DSR is turned off for 1 or 2 seconds upon a disconnection.
&S3
The status of DSR follows DTR.
&S4
DSR on early. This option should not be used unless it is
expressly needed to be compatible with an external
autodialer device. The ISDN TA/V operates as per standard
RS-232 signaling except that DSR comes on immediately
when the ISDN TA/V establishes a physical connection to a
remote device. This option violates the ITU requirements for
control of DSR.
&S5
Delay until data. The ISDN TA/V operates as per standard
RS-232 signaling except that DSR comes on when the ISDN
TA/V goes into data mode, which is when CTS and DCD
normally come on. This option is intended for use with DTEs
which cannot operate with the long RTS/CTS delay which is
inherent in V.32bis.