Keithley 2657A, Reference Manual, Page: 106 / 805

Section 2: General operation Model 2657A High Power System SourceMeter® Instrument Reference Manual
2-82 2657A-901-01 Rev. B/December 2012
When the LED is: The network:
Off is not connected
On is connected
Blinking is sending or receiving data
Using the LAN with remote operations
The following table lists the Model 2657A remote interface's available LAN protocols:
LAN protocols
Port number Protocol
23 Telnet
1024 VXI-11
5025 Raw socket
5030 Dead socket termination port
You can only use one remote interface at a time. Although multiple ethernet connections to the
instrument can be opened, only one can be used to control the instrument at a time.
Raw socket:
Raw socket is a basic ethernet connection that communicates similarly to RS-232
without explicit message boundaries. The instrument will always terminate messages with a line feed,
but because binary data may include bytes that resemble line feed characters, it may be difficult to
distinguish between data and line feed characters.
VXI-11:
VXI-11 is similar to GPIB and supports message boundaries and service requests (SRQs). A
VXI-11 driver or VISA software is required. Test Script Builder (TSB) uses VISA and can be used with
the VXI-11 interface.
Telnet:
Telnet is similar to raw socket and is used when you need to interact directly with the
instrument, typically for debugging and troubleshooting. Telnet requires a separate telnet program.
Dead socket termination port:
The dead socket termination port is used to terminate all existing
LAN connections. A dead socket is one that is held open by the instrument because it has not been
properly closed. This most often happens when the computer is turned off or reboots without first
closing the socket. This port cannot be used for command and control functions.
Monitoring the LAN
The
lan.autoconnect
command configures the instrument to monitor the LAN for lost connections.
All ethernet connections are disconnected if the LAN link is disconnected for longer than the time-out
value specified in the
lan.linktimeout
attribute.
NOTE