Here's a little bit of "review" information that will be helpful in understanding one form of the command; packet data is sent by alternating between two audio tones when transmitting in AFSK mode. In FSK mode, it alternates between two radio frequencies. The CALIBRATE command allows you to send alternating audio or radio tones for up to 60 seconds.
Additionally, you can specify how long to alternate the tones within the transmit time period of the command. The syntax of the CALIBRATE command is:
CALIBRATE (total transmit time, 1-60 seconds) (toggle interval)
The command can also be shortened to CAL. Here's an example of usage:
CAL 20 10
This would set the node to transmit for 10 seconds at one of the audio tones, and 10 seconds of the other tone for a total of 20 seconds.
One special note concerning this command - remember that your TNC has a time-out timer to keep the node from transmitting too long should the node lock up. If that timer is set for 30 seconds and you specify a calibration trasnmission of 60 seconds, you'll only get a 30 second transmisison.
CLOSEDOWN A
This command is almost self-explanatory. When issued, the node will prompt you for the Sysop password, just as if you had entered the SYSOP command. I will not detail exactly how the SYSOP command works for security reasons.
Once you have successfully given the correct SYSOP response, the node will stop transmitting and can't be accessed. No routing tables or other operating parameters will be removed from the node's memory. However, in order to reactivate the node, a power-up reset will need to be performed. This means you will have to go to the node site and cycle the power off and then back on. Therefore, caution is in order - you will want to carefully consider whether you really want to use the CLOSEDOWN command.
CTEXT
This command sets or clears the text that users will see when they connect to the node. It takes the same form as other text commands, such as BTEXT. For example,
CTEXT Welcome to the WAPR Network Node!
Causes the node to return "Welcome to the WAPR Network Node!" when a user connects to the node.
There are two things to consider when entering the connect text. Like other text commands, the connect text is limited to 160 bytes, which is enough for 80 characters (including letters, spaces, and control characters). If you forget to clear the existing text, whatever you enter will be added to the existing text.
DXCLUSTER WX9APR-1
This will set the DXCLUSTER to WX9APR-1. A node user will be connected to this station when the DX command is sent to the node.
For example, if a DX Cluster node or station is not operating on a local LAN frequency and is accessable to the node through the network, a user can simply send a connect request to the DX Cluster alias and be connected via the node. This appears as a transparent connection to the user, as though he or she were connected directly to the DX Cluster station. In fact, the node is acting on behalf of the node, "faking it".
As with DXCLUSTER, the command takes three forms:
DXCALIAS *
Clears the current alias.
DXCALIAS ?
Displays the current alias, and
DXCALIAS (call-sign or alias)
will set the DXCALIAS to the specified call-sign or alias. Here's an example:
DXCALIAS WAPRDX
will allow a user to send a connect request to WAPRDX and get connected to a remote DX Cluster as set by the DXCLUSTER command. In the above example we used for the DXCLUSTER command, this would be WX9APR-1.
One thing that should be noted concerning any alias-based command. If you are going to be using a someone else's call-sign rather than an alias, you should inform the owner of that call-sign and get his or her cooperation. After all, the call-sign belongs to someone else, and they should know that you're node will respond to that call-sign.
That's all for this installment. Next time, we'll continue our alphabetical
exploration of the Sysop commands for these nodes.