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5-3

Advanced Command Naming Topics:

You probably don't need to read this section, but it is here just in case. If it doesn't make sense to
you, just skip it.

The controller has a table which it uses to keep track of the information for each command. This
information is used when the controller tries to find out what command you have entered the name
for. If more than one command has the same name, it can also be used to intelligently figure out
which one you wanted. Some of the entries are:

Command name (including the length of the name).
Data length: that is how many digits, if any, are needed after the command name.
If the data length is not zero, whether the amount must be exact or whether more digits can be
entered.
DTMF execution mask (see command 130)
User level required to execute (see Chapter 18)

For example, command 009 would have a data length of zero, command 000 would have a data
length of 2 which must be exact, and command 030 would have a minimum data length of 2, but
could be longer. Other checking such as making sure that the data for 030 is a multiple of two
digits and limiting the maximum length is done by the commands themselves. Where the checking
is done is important. The checks that can be done with the information in the table can be used to
help figure out which command you want to execute when the names are ambiguous, while the
checks that are done within the commands themselves are too late and will cause error messages if
they are not satisfied.

When you enter a command and unkey or press enter, the controller scans the whole table of
commands looking for a match. It ignores any commands that would be blocked by the DTMF
execution mask or that require that you log on using a password to execute (unless you have logged
on). It also ignores any that it knows have the wrong number of data digits after the command
name (using the information in the table as discussed above), although there are some cases where it
can't tell until the command is chosen and causes an error. From the remaining commands, it
chooses the one with the longest name that matches what was entered. In case of a tie, it chooses
the one with the lowest command number.

For example, if you have commands named "1", "12", "123", "1234" and "12345" and you enter
"12399", assuming that all of them pass the initial execution mask and password and data length
checks, the controller will select the command named "123" and will execute it with the data digits
"99". That is it will find the longest match, then use the rest of the digits as data. Keep this in mind
when you change command names to be less than three digits.

This ability of the controller to find the longest matching name can be used in several practical
ways. For example, command 000 connects two ports together. It normally sends "X connect Y"
as the voice response. If you have a repeater on port 1 and a link to another site on port 2, you
might want the message to be "Link up" instead. You could make a macro named "00012" or
"00021" that would connect the two ports and send that message. Then entering "00012" or
"00021" would cause your custom message to be sent, while "00013" or any other command