Measurement Computing Parallel488 - Manual (Page 28)

Section 4 IEEE to Parallel Operation
4.4
DIO5 Not Defined - Always "0"
DIO4 Not Defined - Always "0"
DIO3 Not Defined - Always "0"
DIO2 IEEE Input Buffer Full
When this bit is set, it indicates that the Parallel488 may hold off the
controller on subsequent data transfers. The interface may continue
to accept an additional 512 characters.
DIO1 IEEE Input Buffer Empty
When this bit is set, it indicates that the parallel device has accepted
all previous data sent to the Parallel488.
4.4 IEEE 488 Bus Implementation
The Parallel488 implements many of the capabilities defined by the IEEE 488
1978 specification. These are discussed in the following sections. The bus uniline and
multiline commands that the Parallel488 does not support or respond to include:
Remote Enable (REN)
Go to Local (GTL)
Group Execute Trigger (GET)
Local Lockout (LLO)
Take Control (TCT)
Parallel Poll (PP)
Parallel Poll Configure (PPC)
Parallel Poll Unconfigure (PPU)
Parallel Poll Disable (PPD)
4.4.1 My Talk Address (MTA)
The Parallel488 does not support the transfer of data from the parallel port
to the IEEE controller except as it pertains to serial polls. This is due to the
unidirectional data transfer of the parallel interface.