The TNC, or Terminal Node Controller, that "little black box of tricks" we've talked about in the past, has more than 100 different commands for you to use. You're able to to customize your packet operating with these commands and turn on and off various features as you wish. Not all TNC's are exactly alike, but all have pretty much the same functions. I'll be using the commands used by the TNC2 and clones in my examples.
We covered a few of the commands previously: CONTROL C for entering command mode,
Mycall, Monitor, Connect, and Disconnect. Now lets discuss a few that can change the way your station functions.
This command tells the TNC whether or not it should send what you type back to the monitor screen. If you don't see anything when you type, set ECHO to ON. If yyoouu ssee ddoouubbllee, like that, set ECHO OFF. This setting will depend on how your particular computer system functions.
(converse mode) Your TNC will automatically switch to this mode when you connect with someone, but you can also do it by entering CONV (CR) at the Cmd: prompt. When in converse mode, anything you type will be transmitted via the path you set with UNPROTO. (See Next Paragragh.) Anyone in monitor mode will be able to read what you transmit. Packets in converse mode are sent only once and are not acknowledged, so there is no guarenteer that they'll get through. This mode is used frequently for sending CQ's.
This command designates the path used when in converse mode. The default is CQ, but you can enter a series of digipeaters if you wish, or a specific group or club name. Some examples: CQ v ZL0STB,ZL1IT PBBS v ZL1BW,ZL1IT
Remember, you have to change UNPROTO for use on different frequencies, unless you leave it set simply to "CQ".
This determines how long your TNC will wait for an acknowledgement before resending a packet. It shouldn't be set too short, or you simly clutter up the frequency, yet it shouldn't be too long, or you'll spend too much time waiting. I use FRACK set to 7, and have found that to be an overall good value.
Used to avoid collisions, DWAIT is the number of time units the TNC will wait after hearing data on the channel before it transmits. I have DWAIT set to 16, and have found that to work well.
Determines the number of characters in your packets, ranging from 1 to 256. The more characters you send per packet, the longer it takes to transmit the information and your chances are of noise, interference or another station wiping it out. I've found a PACLEN of 80, which is the length of one line, to be a good value. When working a station nearby, PACLEN can be increased. When working a distant station, it should be decrease.
Your TNC will retransmit a packet if it doesn't receive an acknowledgement from the station you're working. RETRY indicates the number of times the TNC will try to get the packet through before giving up and disconnecting. This can be set from 1 to 15, but I've found 8 to 10 to work well. Less than that causes an unnecessary disconnect if the channel happens to be busy, but more than that clutters up the channel.
This must be ON for you to monitor anything. When ON, you see packets
from other stations on the frequency you're tuned to. What packets you see is
determined by other commands from the list below. if MONITOR is OFF, you
only see packets sent to you while you're connected to another station.
If MALL is ON, you receive packets from other stations that are connected to other
stations, as well as packets sent to unproto (unconnected) mode. This should be ON for "reading the mail". If MALL is OFF, you receive only packet sent in unproto mode by
If on, you see connect <C>, disconnect <D>, acknowledge <UA> and
busy <DM> frames in addition to information packets <I1>. If OFF, only information
packets are seen.
If ON, you see packets from other stations while you're connected to
someone else. This can get very confusing, but is useful when your path is bad
and you want to see if your packets are being digipeated okay. If OFF, the monitoring of other stations is stopped when you're connected to another station.
If ON, you see a display of all the stations used as digipeaters along with his station originating the packet and the destination station. If OFF, you see only the originating
and destination stations. For example, if you have MRPT ON, you might see a transmission
such as this:
ZL1BW>ZL1NG,ZL1IT-1*:I'LL BE LEAVING NOW!
If MRPT OFF, the same transmission would look like this:
ZL1BW>ZL1NG:I'LL BE LEAVING NOW!
In the first case, you can see that the ZL1IT-1 digipeater was being used. The asterick indicates which station you were hearing the packet from. In the second case you have no idea if digipeaters are being used or what station you were receiving.
If you have this turned ON, the header of each packet is printed on a separate
line from the text. If OFF, both the header and packet text are printed on the same line.
Monitored packets show the date and the time the packet was received if MSTAMP is ON. If it's OFF, date/time stamp is not shown.
NOTE: The date and time must be entered using the daytime command before the MSTAMP command will function.