No Operation (Nop); Sense Type And Model (Stm) - IBM 6400 Programmer's Reference Manual

Device Control Command Set
expressed in terms of the units in effect at the time the LPP command is
received.
Only positive values are valid for the data field. The format of the data field
(DATA) for this command is:

No Operation (NOP)

Length D603 Flag
An NOP command is valid in any printer state. The printer does not perform any
operation as a result of receiving this command. The printer ignores any data in
this command.

Sense Type and Model (STM)

Length D6E4 Flag
This command is valid in any state. The Sense Type and Model command
requests the printer to respond with the printer's type and model information and
the functions it supports. The printer returns this information to the host
application program in the Special Data (SD) portion of the Acknowledge Reply
to the STM command (see "Acknowledge Reply (ACK)" on page 29).
This command is effectively a NOP if the ARQ bit is not on in the command
header.
Acknowledge Reply for Sense Type and Model
The format of the data field returned with the Acknowledge Reply is:
acknowledgment type, page or copy counters, and 6 bytes of general
information, followed by a sequence of command set vectors identifying the
functions supported by this printer. The following chart shows the Data field:
42
6400 IPDS
Table 15. Logical Page Position
Byte Value
0 X ' 00 '
1-3 X FF8000
'
4 X 00
' '
5-7 X FF8000
'
8-9 X 0000
' '
Correlation ID
(Optional)
Correlation ID
(Optional)
Length D6FF Flag
Description
Reserved
- X 007FFF X Coordinate of the
' ' '
Logical Page Origin
in L-Units
Reserved
- X 007FFF Y Coordinate of the
' ' '
Logical Page Origin
in L-Units
Reserved
DATA
Correlation ID
Error Code
X 02AD..01
'
X 02AD..01
'
Data
'
'