Instruction manual

Appendix B – Telnet (Terminal) Commands
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Instruction Manual – DXLink™ Fiber Transmitters and Receivers, Duplex
TCP – Protocol has a built-in retry mechanism.
UDP – Protocol does not have a built-in retry mechanism, but consumes fewer resources on the Master.
AMX’s UDP implementation of NetLinx employs a retry mechanism to provide the reliability of TCP with
the resource efficiency of UDP.
URL vs. NDP vs. Auto
Determining which connection method to use for Master Connection Mode is essentially a matter of deciding what
information the device should use to identify the correct Master to connect to.
The default mode is NDP; the mode can be changed via the SET CONNECTION Telnet command (see page 101).
URL – The device connects to the Master with the specified URL. The device must be configured with the
URL of a specific Master via the SET CONNECTION Telnet command (see page 101).
NDP – The device connects to the Master it’s been bound to, which is based on the Master’s MAC address.
The binding is configured via NetLinx Studio. Once bound, the device must be unbound using either NetLinx
Studio or the NDP UNBIND Telnet command before being re-bound to a different Master.
Alternatively, NDP devices can be bound/unbound via options on the Master’s Web Configuration pages
(System > Manage NetLinx). For details, refer to the NetLinx Integrated Controllers - WebConsole &
Programming Guide (see section on “System - Manage NetLinx”).
Auto – The device connects to the first Master it finds with the specified System Number.
The device must be configured with the desired system number via the SET CONNECTION Telnet command
(see page 101).
Use of this method requires that only one Master has any particular system number and is visible to the
subnet. If this is the case, then Auto is the simplest choice. However, with Auto, you are not hard-bound to a
particular Master. Therefore, if at some point in the future, another Master is configured with the same system
number, the result is that the DXLink Fiber unit could show up on that other Master.
Notes on Specific Telnet Clients
Telnet and terminal clients exhibit different behaviors in some situations. This section states some of the known
anomalies.
Windows Client Programs
Anomalies occur when using a Windows
®
client if you are not typing standard ASCII characters (i.e., using the keypad
and the Alt key to enter decimal codes). Most programs will allow you to enter specific decimal codes by holding Alt
and using keypad numbers.
Example
For example, hold Alt, hit the keypad 1, then hit keypad 0, then release Alt. The standard line feed code is entered
(decimal 10). Windows will perform an ANSI to OEM conversion on some codes entered this way because of the way
Windows handles languages and code pages.
The following codes are known to be altered, but others may be affected depending on the computer’s setup.
Characters 15, 21, 22, and any characters above 127.
This affects both Windows Telnet and terminal emulation programs.
Linux Telnet Client
The Linux Telnet client has three anomalies that are known at this time:
A null (\00) character is sent after a carriage return.
If an “Alt 255” is entered, two of the “255” characters are sent (per the Telnet RAFT).
If the code to return to Command mode is entered (Alt 29 which is ^]), the character is not sent, but the Telnet
Command Mode is entered.