Transmission Sequences - IBM 5256-1 Maintenance Information Manual

Transmission Sequences
Controller (Work Station Attachment)
Fill Bits (always 000)
Parity Bit for Even Parity
End of Message (111)
Receive
Work Station
Fill Bits (always 000)
Parity Bit for Even Parity
Work Station Address (000 through 110)
I
command Modifier
1
Command Modifier
_ - L - _ [
Com~nIir,nc
[
Comman[:~nc
Bit
o 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 2 3 4 5 6 7 8 9 10 11 12 13 14 15
10 0 0 1 P 11 1 Ix x x x x x x x 11
I I
0 0 0 1 P I@ @ @I x x x x x x x x 11 10001111 1 1 1 I
~
_ _ _ _ _ _ _ _ _ _ _ _ _ _
~~
_ _ _ _ _ _ _ _ _ _ _ _ _ _
~J ~
, J ,
I'~
__
~
____
~I
Last Frame Additional First Frame Frame
Frames Synchro-
nization
(6 half bits)
Work Station Transmit Controller (Work Station Attachment)
Fill bits
(always 000)
Fill bits
(always 000)
Parity Bit for Even Parity Parity Bit for Even Parity
l
End of Message (111) l w o r k Station Address (000 through 110)
[
Status
I
Stat4~
[
Sync [
Sync Bit
_ - - - L _ _ _ ' - _ _ _ _ _ ' - - _ _ _ _
Bit _--'-__
...JL. _
o 23456789101112131415 0 23456789101112131415
Bit
Synchro-
nization
1000lpI1 11x x x x x x x xl11 100 olpl@@@lx x x x x x x xl1100011111 1 1 11
~
______________
~~
______________
~/~ ~L\::::::~~::::~::;:::::::::::::::::;J~'::~::/*\_=-=-=-=-~~=-::-=~_I
~,
w ¥ -
Last Frame Additional First Frame Frame
Bit
Synchro-
nization
Frames Synchro-
Note: For scope procedures and pictures, refer to the
controller documentation.
The 16-bit frame carries 13 bits of information in each
direction. The fill bits, always 000, serve as a timing
delay. The parity bit makes the active bits in the frame
even. The printer decodes the address bits and
responds to a specific address. The printer sends a
response frame that contains the station address. A
printer address of 111 indicates an end-of-message and
causes line turnaround. (At the work station, line
nization
(6
half bits)
turnaround extends from the time the last bit of a frame
(bit 0) is received until the same work station starts
sending bit and frame synchronization patterns.) Bits 7
through 14 are the data or commands used throughout
the printer and storage. Bit 15 (always on) is the
synchronization bit for both the controller and the
printer.
Theory,
Features
Theory
5256 MIM 4-7