User`s manual

Table 3-8 (Cont)
Control Status Register Bit Assignments
Bit(s)
Designation
Function Read/Write
12
DSR
Set to 1 whenever an ON to OFF or OFF to ON
Read only
(Data Set Ready
transition occurs on the
DSR status line from the
transition)
selected modem. Not valid
if the PDP-II program
(Synchronous
has changed
the line number in CSR bits 0-3 and
modem definition)
the scan has
not been cycled for one or more lines
by Scan En (CSR bit 5) or Step (CSR bit 8). Cleared
by Initialize or Clr Scan.
12
SECRX
Set to a I whenever an ON to OFF or OFF to ON
Read only
(Secondary Receive
transition occurs
on the SEC RX status line from
transition)
the selected modem. Not valid
if the PDP-II pro-
(Asynchronous
gram has changed the line
number in CSR bits 0-3
modem definition)
and the scan has
not been cycled for one or more
lines
by Scan En (CSR bit 5) or Step (CSR bit 8).
Cleared by Initialize or Clr Scan.
13 CS
Set to I whenever an ON to OFF or OFF to ON
Read only
(Clear to Send
transition occurs on the CS status line from the
transition) selected modem. Not valid if the PDP·! 1 program
has changed the line number in
CSR bits 0-3 and
the scan has nut been cyded fur one or more liIles
by Scan En (CSR bit 5) or Step (CSR bit 8).
Cleared by Initialize or Clr Scan.
14
CO
Set to I whenever an ON to OFF or OFF to ON
Read only
(Carrier On transition occurs on the CO status line from the
transition) selected modem. Not valid
if the PDP-II program
has changed the line number in
CSR bits 0-3 and
the scan
has not been cycled for one or more lines
by Scan En (CSR bit 5) or Step (CSR bit 8).
Cleared by Initialize or Clr Scan.
15
RING
Set
to 1 whenever an OFF to ON transition occurs
Read only
(Ring
Signal) on the RING status line from the selected modem.
Not valid
if the PDP-II program has changed the
line number in
CSR bits 0-3 and the scan has not
been cycled for one or more lines by Scan En
(CSR bit 5) or Step (CSR bit 8). Cleared by
Initialize or Clr Scan.
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