HP 16500L Installation And Service Manual page 49

Programming the HP 16500B
The Command Parser Socket
You can TELNET to the HP 16500B command parser socket and send
programming commands directly, or you can write a program that
opens the socket and sends commands to it.
Connection to the command parser socket is, by definition, a control
user connection. Because only one control user connection is
allowed, you will not be able to connect to the command parser socket
if someone else is accessing the HP 16500B's file system as the control
user.
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