National Instruments GPIB-PC - Manual (Page 241)

Appendix C Differences Between Software Revisions
©National Instruments Corp. C-3 GPIB-PC User Manual
Asynchronous I/O
There is no asynchronous capability on Rev. D. If you call an
asynchronous function (
IBRDA , IBRDIA , IBWRTA , IBWRTIA ,
IBCMDA , and IBSTOP ) the ECAP error is returned immediately.
DMA on the GPIB-PCIII
The GPIB-PCIII board has additional DMA capability. If you have the
GPIB-PCIII, consult the
READ.ME file of the accompanying Distribution
Diskette for details.
Local Lockout
In Rev. D there is no automatic local lockout configuration setting.
Therefore, Rev. D does not place devices in lockout.
SRQI Status Bit
In Rev. D the SRQI status bit always reflects the current level of the
SRQ line whether or not the GPIB-PC is CIC.
ATN and/or TIMO
With the IBWAIT function, it is not possible to wait for the ATN or
TIMO conditions. If no other conditions exist, the function returns
immediately.
DCAS and DTAS Status Bits
In Rev. D, these bits are cleared at the beginning of a new function call.
Thus, if the application program must be sensitive to the messages
Device Clear, Selected Device Clear, or Group Executive Trigger, the
status bits must be checked after each function call.
Printer Support
Rev. C has printer support and Rev. D does not.