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AR-210 Manual
3-7
will want to use the Transparent Mode (a data mode like the Converse Mode, except there are no
special characters).
Everything you type, or everything your computer sends to the TNC, is sent over the radio exactly
as it appears to the TNC.
Packets are sent at regular time intervals or when a full packet of information is ready. You may
use the
PACTIME
command to change the time intervals at which data is put into packet form.
The display characteristics of the TNC are also modified in the Transparent Mode. Data is sent from
the TNC to the terminal exactly as it is received over the radio channel, including all eight bits of
each byte received. All features such as LINE FEED and RETURN insertion, ESCAPE translation and
case conversion are disabled. None of the parameters which control these features in the Converse
Mode are changed when you enter the Transparent Mode and all display features are re-enabled
when you return the TNC to the Command Mode. Most of the informative messages that appear in
the Converse Mode as the TNC moves between the disconnected and connected states are also
disabled.
If you wish to escape from the Transparent Mode to the Commend Mode, you must use the follow-
ing procedure.
After a time equal to
PACTIME
has elapsed, the last data you typed will have been put into
packet form for transmission (although it may not have been transmitted yet).
1. Wait for
PACTIME
to elapse. Then wait an additional time, which is set by the
CMDTIME
com-
mand.
2. Type [
CTRL-C
] three times within an interval
CMDTIME
of each other.
After a final
CMDTIME
interval in which you did not type any characters, you will see the '
'
cmd:
prompt. If you type any character in this interval, even if they are more command characters, the
escape will be aborted and the three command characters will be sent as packet data. If you set
CMDTIME
or
PACTIME
to
0
, you will not be able to escape from the Transparent Mode except by
performing a hard reset (power-down reset).
FLOW CONTROL
Whenever you transfer data to computer, there is a chance that the data will be received faster
that the computer can handle it. To prevent loss of data, the computer must be able to make
whatever is sending data stop sending and later tell it to resume sending.
If you are a home computer user, you are probably already familiar with one type of flow control,
which allows you to stop the output from the computer while you read it and restart it when you
have finished.
There are two methods of providing flow control that are supported by the TNC, XON/XOFF flow
control, sometimes called "software flow control", is accomplished by sending a special character
(usually a CTRL-S) to request that the output stop and another special character (usually a CTRL-
Q) to restart the output.
Hardware flow control may be used if both computers use the RTS (Request To Send) and CTS
(Clear To Send) lines of the RS-232C interface.
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