kiss-tnc

A pure JavaScript module that implements sending and receiving AX.25 KISS frames as a NodeJS stream.

To install

``sh
npm install kiss-tnc
`

Dependencies

kiss-tnc has no dependencies other than NodeJS Stream Transform.

Usage

$3

The KISSSender presumes that it will be streamed data to send as NodeJS Buffers of the appropriate length for your communication setup.

`js
// Require the package
const { KISSSender } = require('kiss-tnc');

// Instantiate the sending stream with your hardware and communication options
const mySendStream = new KISSSender({
portIndex: 12,
fullDuplex: false,
hardware: 'hardware configuration string',
persistence: 16,
slotTime: 100,
txDelay: 100,
txTail: 100,
});

// Create the stream to send the formatted KISS frames to
const SerialPort = require('serialport')
const port = new SerialPort('/dev/tty-usbserial1', { baudRate: 9600 });

// Connect the KISS framer to the serial destination
mySendStream.pipe(port);

// Once piped, our send stream will send our initialization information to
// the TNC:
// =>
// => c0 : Frame Start Character
// => c6 : c=12 (Port Index) | 6=6 (Set Hardware Command)
// => 68 - 67 : 'hardware configuration string' as Buffer
// => c0 : Frame End Character

// =>
// => c0 : Frame Start Character
// => c2 : c=12 (Port Index) | 2=2 (Persistence Command)
// => 10 : 16 (Persistence Value)
// => c0 : Frame End Character

// =>
// => c0 : Frame Start Character
// => c3 : c=12 (Port Index) | 3=3 (SlotTime Command)
// => 0a : 10, SlotTime value divided by 10ms
// => c0 : Frame End Character

// Each property other than portIndex passed to the KISSSender constructor
// e.g. persistence, slotTime, txDelay, etc, will generate a data frame
// sent to the TNC with the appropriate framing bytes, command byte, and
// values.

// Write data to the KISS stream
mySendStream.write(Buffer.from('Hello, world!'));

// What is sent on to the TNC:
// =>
// => c0 : Frame Start Character
// => c0 : c=12 (Port Index) | 0=Data Follows
// => 68 : 'h'
// => 65 : 'e'
// => 6c : 'l'
// => 6c : 'l'
// => 6f : 'o'
// => 2c : ','
// => 20 : Space Character
// => 77 : 'w'
// => 6f : 'o'
// => 72 : 'r'
// => 6c : 'l'
// => 64 : 'd'
// => 21 : '!'
// => c0 : Frame End Character

// Write bytes to the TNC that need to be escaped
mySendStream.write(Buffer.from([192, 219]));

// =>
// => c0 : Frame Start Character
// => c0 : c=12 (Port Index) | 0=Data Follows
// => db : 219 (Escape Character)
// => dc : 220 (Escaped 192)
// => db : 219 (Escape Character)
// => dd : 221 (Escaped 219)
// => c0 : Frame End Character
`

Now let's set up our stream for receiving incoming data from a TNC.

`js
// Require the package
const { KISSReceiver } = require('kiss-tnc');

// Instantiate the receiving stream
const myReceiveStream = new KISSReceiver();

// Create the stream from which we'll receive TNC data
const SerialPort = require('serialport')
const port = new SerialPort('/dev/tty-usbserial1', { baudRate: 9600 });

// Connect the streams
port.pipe(myReceiveStream);

// Set up a data listener for our receive stream
myReceiveStream.on('data', data => {
console.log(' Received a frame ');
console.log(data);
console.log(data.toString());
});

// Now myReceiveStream can accept partial data, and will emit complete
// frames once the end byte is received from the source stream.
port.write(Buffer.from([192, 160]));
port.write(Buffer.from('hello'));
port.write(Buffer.from(' wor'));
port.write(Buffer.from('ld!'));
port.write(Buffer.from([192]));
// => Received a frame
// =>
// => hello world!
`
Now you can handle each frame as a unit. We can also receive the frames as an object as well:
`js
const myObjectReceiveStream = new KISSReceiver({ emitObject: true });

myObjectReceiveStream.on('data', dataObj => {
const { portIndex, data } = dataObj;

console.log(' Received an object frame ');
console.log('port index', portIndex);
console.log(data.toString());
});

port.write(Buffer.from([192, 160].concat('hello world!'.split('')).concat(192)));

// => Received an object frame
// => port index 8
// => hello world!
``