Table of Contents
Mnemonic
Operand
NES
I
AND EXTERNAL STATUS
LINES TO Z
NES 1
NES 2
NES 3
NES 4
NES 5
NES 6
NES 7
NES 8
·Character Ready
Auxiliary-Status Line (Line Turn Around)
Call in Progress
Request to Answer Call
Auxiliary Status Line (Space Detect)
Auxiliary Status Line
Auxiliary Status Line
Auxiliary Status Line
RECEIVE OPERATION
Word Times
1
1
1
1
1
1
1
1
1
The RPU will accept any parallel .character occupying up to 14 channels. The number of channels
can be reduced to fit the code in use when fewer than 14 channels are used.
Characters are transferred to the least significant bit positions of the DATANET-30 word. The
least significant digit of the character will be transferred to Y -ZO 1, the second least significant
digit to Y-Z02, etc.
The RPU is a single buffer device. ·The character being received will exist in the single buffer
for only one character time.
As the transmitting device transmits each succeeding character,
the new character appears in the buffer immediately. A character must be shifted out of the
buffer before the next one is received (transmitted) or the character in the buffer will be lost.
Assume that nothing is being received, and that the RPU is in a state to receive data. When a
character is received it is sent to the receive buffer and a flag is set. The program has been
periodically interrogating the state of the flag. When the flag is set, and when the program detects
this condition, the character is transferred out of the RPU buffer and the flag is reset.
The RPU is capable of utilizing automatic answering and answer-back features of the digital
subset.
Both hardware automatic answering and program answering can be done. Hardware
answering is done by the digital subset.
When the digital subset answers, the external status
line (ESL 3)-call-in-progress signal will be set until the call is terminated. The program can
terminate a call with a Drive External Function (DEF 10)-Disconnect Call instruction.
When the program does the automatic answering, upon the receipt of an incoming call, an External
Status Line (ESL 4) signal -- request to answer call -- is set, but the call is not answered
until the program can do so.
The program can answer with a Drive External Function (DEF 9)
[ID&lr&~~tr~ ~@------------
V-32
Table of Contents
