CONNECT COMPUTER
4
Connecting the TNC to Your Computer
RS-232/TTL Jumper
Jumpers are appropriately labeled on the PC board. Refer to the parts location diagram for help in
locating them. Also refer to the Assembly and Disassembly section for information on obtaining ac-
cess to the interior of the TNC.
KAM Jumper K7
KPC-4 Jumper K10
KPC-2 Jumper K2
KPC-2400 Jumper K2
KPC-1 Jumper K2
This jumper is provided to change the TNC from RS-232 to TTL operating voltage levels. All TNCs
are shipped from the factory in the RS-232 position. If your computer operates at TTL level volt-
ages, reposition this jumper prior to placing the TNC in service.
TNC to Computer Connection
The TNC is connected to the serial data port of your computer and a terminal program must be
loaded into your computer. The serial port provides a place for data to be sent to or received from
the TNC. The terminal program is the software which runs in the computer, allowing it to commu-
nicate with the TNC. This is also sometimes called a communication program.
A few computer systems include a terminal program on the system diskette or in the initial soft-
ware package, usually named COMM, TERM or a similar name which conveys the idea of communi-
cating. Some computer system require that a terminal program be obtained separately. Several
simple terminal programs have been included in the Sample Terminal Programs section to assist
you. In general, any program which allows telephone modem communications with the computer
will be suitable for use with the TNC. A special program will be needed for the display of WEFAX
pictures.
There are generally four variables to be set in your terminal program. These are baud rate, parity,
word length (also called data bits) and the number of stop bits. If your terminal program provides
for these variables, use the following settings to talk to the TNC:
Baud rate: 300, 600, 1200, 1800, 2400, 4800 or 9600
Parity: None
Data bits: 8
Stop bits: 1
The 25-pin connector on the back panel of the TNC is for connecting to the computer. (The KPC-4
has a 9-pin connector.) When facing the back of the back of the TNC the connector on the right
side is labeled COMPUTER. See page 3 for back panel diagrams.
Cable Wiring
A cable is provided with five pre-wired lines for the connector. You must provide the connector to
attach these lines to your computer serial port. In most cases, unless the terminal program you
use requires hardware flow control, you need only connect three of these lines – Transmit Data,
Receive Data and Signal Ground. For hardware flow control, also called RTS/CTS handshaking, all
five wires in the provided cable are required.
To Next Page
Loading...
