2-8
IM WT310E-17EN
2.5 Responses to Interface Messages
Multi-line Messages
Eight data lines are used to transmit multi-line messages. The messages are classified as follows:
• Address Commands
Some address commands are valid when a device is designated as a listener, and some are
valid when it is designated as a talker. The following five commands are available.
Commands available to a device designated as a listener
• GTL (Go To Local)
• SDC (Selected Device Clear)
• PPC (Parallel Poll Configure)
• GET (Group Execute Trigger)
Commands available to a device designated as a talker
• TCT (Take Control)
• Universal Commands
Universal commands are available to all devices regardless of their listener or talker designation.
The following five commands are available.
• LLO (Local Lockout)
• DCL (Device Clear)
• PPU (Parallel Poll Unconfigure)
• SPE (Serial Poll Enable)
• SPD (Serial Poll Disable)
There are other interface messages: listener-address, talk-address, and secondary commands.
Interface messages
Uni-line
messages
Address
commands
Universal
commands
IFC*
REN*
IDY
GTL*
SDC*
PPC
GET*
TCT
LLO*
DCL*
PPU
SPE*
SPD*
Listener
Address
Talker
Address
2
Command
Multi-line Messages
This instrument supports interface messages marked with an asterisk.
Note
Difference between SDC and DCL
In multi-line messages, SDC messages are those that require talker or listener designation and DCL
messages are those that do not require a designation. Therefore, SDC messages are directed at a particular
instrument while DCL messages are directed at all instruments on the bus.