RCA 70/700 Series Reference Manual page 58

Table 3-4. Line Status Words (LSW)
(Cont'd)
Item Bit
Function Operation
Description Assign
SYN sequence counter
C14 to C16
Line synchronization establishment Used to generate appropriate number of
and maintenance. SYN characters when initiating syn-
chronous transmission and permits
counting of incoming SYN characters to
establish synchronization when receiving.
Parity C17
Block parity DO toD 8 Accumulated block parity Binary add without carry of each
character storage.
character .'
Character counter
D9 to D16
Character count.
Incremented on each character to or from
processor.
Parity
D17
Interrupt pending EO to El Pending termination interrupt Set by SET INT command or lead from
or PCI indication. MPX channel. Reset when interrupt
reported.
Standard Device byte E2 to E5 Assembly of standard device byte.
Line operation
E6, E7 Buffer (line) command status. Set on receipt of Write, Write Control, or
(Buffer is input/output)
Read command from processor. Reset on
END.
E7 E6
0 0
Quiescent
0 1 Read Command
1 0
Write Command
1 1
Write Control
Inactive line E8 Indicates when device address
Set to 1 by program for all inactive device
not occupied or buffer cannot addresses at initialization. An address
accept any commands. (command) sent to a device address with
this bit set is ignored (Ready is not re-
turned by the CCM).