Kantronics MT1200, Руководство пользователя, Страница: 58 / 157

Therefore the Connected Mode, barring impossible conditions, assures that the station
you are connected to will receive everything you say, and in the order you say it.
In the Unproto Mode, when your TNC sends a packet, no acknowledgment is expected
and no retries are attempted. This mode is often used for calling CQ, for transmitting
beacons, and for informal round table chats.
Monitoring and Calling CQ
If you set the MONITOR command to ON, you will see other station’s packets on your
screen. You will notice two callsigns at the beginning of each packet separated by a “>”.
The first callsign is the station the packet is from, and the second callsign is the station
the packet is to. An Unproto packet may have a name or CQ for the second callsign.
To set what will be seen as the “to” callsign for Unproto packets you send, you use the
UNPROTO command. This comes defaulted as CQ.
In order to call CQ you must get into the Convers Mode, so that what you are typing to
the TNC will be interpreted as data to be sent out on the air and not as commands. To
do this type:
K<CR>
The <CR> indicates a “carriage return” or pressing the “ENTER” key on your keyboard.
Now anything you type will be packetized and sent out on the air. Remember to get
back to Command Mode you enter a <Ctrl+C> (default) by holding down the Control key
while pressing “C”. You will be going between Command and Convers Modes
depending on whether you want to talk to the TNC or have the TNC packetize what you
type to go out on the air.
Flow Control
The flow control commands insure that the TNC gets everything that is sent to it by the
computer and that the computer gets everything the TNC sends it. When the computer
sends the TNC data, the TNC stores this data in a buffer until it can packetize it, send it,
and get acknowledgments. Similarly, when the TNC sends the computer data, the
computer stores the data in a buffer until it can be processed, stored to disk, sent to
printer, or whatever.
This buffer area is of limited size; if more data is sent than will fit in the buffer the extra
data will be lost. To make sure each device gets all the data it should from the other
device, the two devices can tell each other to start and stop sending data. This is called
Flow Control and it can be accomplished in either of two ways, via software or via
hardware.
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