How to use the short_message object with UDH and message properties?

Hi. I’m having trouble using UDH to concatenate the messages. Can someone show me a simple example? The below is what I have tried:

` // begin const config = require(‘…/src/config.json’);

var smpp = require(‘smpp’); var session = smpp.connect(config.smppSession);

smpp.encodings.default = ‘UCS2’;

session.bind_transceiver({ system_id: config.systemId, password: config.systemPassword }, (pdu) => { if (pdu.command_status === 0) {

// here I try to send some messages
session.submit_sm({
  source_addr: config.sourceAddress,
  destination_addr: config.destinationAddress,
  short_message: {
    udh: Buffer.from([0x05, 0x00, 0x03, 0x05, 0x02, 0x01]),
    message: "Hello World!"
  }
}, (pdu) => {
  if (pdu.command_status === 0) {
    console.log("First OK");
  } else {
    console.log("First Error");
  }
});

// here's the second message I want to concatenate with
// the first
session.submit_sm({
  source_addr: config.sourceAddress,
  destination_addr: config.destinationAddress,
  short_message: {
    udh: Buffer.from([0x05, 0x00, 0x03, 0x05, 0x02, 0x02]),
    message: "Hello from Another World!"
  }
}, (pdu) => {
  if (pdu.command_status === 0) {
    console.log("Second OK");
  } else {
    console.log("Second Error");
  }
});

} }); // end `

[ritmas]

Try this code snippet (that’s what I’m using):

/* concatenate SMS */
var messages = [
        'Hello World!',
        'Hello from Another World!'
    ],
    concatRef = Math.floor(Math.random() * 255);
for (var i = 0; i < messages.length; i++) {
    var smsPart = messages[i],
        udh = new Buffer(6);
    udh.write(String.fromCharCode(0x5), 0); /* Length of UDH */
    udh.write(String.fromCharCode(0x0), 1); /* Indicator for concatenated message */
    udh.write(String.fromCharCode(0x3), 2); /* Subheader Length (3 bytes) */
    udh.write(String.fromCharCode(concatRef), 3); /* Same reference for all concatenated messages */
    udh.write(String.fromCharCode(messages.length), 4); /* Number of total messages in the split */
    udh.write(String.fromCharCode(i + 1), 5); /* Sequence number (used by the mobile to concatenate the split messages) */

    session.submit_sm({
        destination_addr: config.destinationAddress,
        source_addr: config.sourceAddress,
        short_message: {udh: udh, message: smsPart}
    }, function(pdu) {
        //
    });
}

If that does not resolve your issue, probably you need to debug on server side.

[hmnk-hdm]

The error turned out to be server side. I’m not sure why and how it was fixed. Sorry. I think some changes were made on server-connection.js file in this https://github.com/Roave/shorty in lib and that caused the issue with UDH messages. After it was fixed, I could run your code. Thanks!