Send Concatinated SMS message using EasySMPP API (How to Add UDH Info) - sms

Question

i am using c# API called EasySMPP, it is pretty great in sending single SMS, it is also good in send large SMS, but the recipient get the messages separately, which is not meaningful, what i am looking is how to modify the PDU so that i can append the UDH info.
How can i achieve adding a UHD info, here is the SubmitSM method from the API,
public int SubmitSM
(
byte sourceAddressTon,
byte sourceAddressNpi,
string sourceAddress,
byte destinationAddressTon,
byte destinationAddressNpi,
destinationAddress,
byte esmClass,
byte protocolId,
byte priorityFlag,
DateTime sheduleDeliveryTime,
DateTime validityPeriod,
byte registeredDelivery,
byte replaceIfPresentFlag,
byte dataCoding,
byte smDefaultMsgId,
byte[] message)
{
try
{
byte[] _destination_addr;
byte[] _source_addr;
byte[] _SUBMIT_SM_PDU;
byte[] _shedule_delivery_time;
byte[] _validity_period;
int _sequence_number;
int pos;
byte _sm_length;
_SUBMIT_SM_PDU = new byte[KernelParameters.MaxPduSize];
////////////////////////////////////////////////////////////////////////////////////////////////
/// Start filling PDU
Tools.CopyIntToArray(0x00000004, _SUBMIT_SM_PDU, 4);
_sequence_number = smscArray.currentSMSC.SequenceNumber;
Tools.CopyIntToArray(_sequence_number, _SUBMIT_SM_PDU, 12);
pos = 16;
_SUBMIT_SM_PDU[pos] = 0x00; //service_type
pos += 1;
_SUBMIT_SM_PDU[pos] = sourceAddressTon;
pos += 1;
_SUBMIT_SM_PDU[pos] = sourceAddressNpi;
pos += 1;
_source_addr = Tools.ConvertStringToByteArray(Tools.GetString(sourceAddress, 20, ""));
Array.Copy(_source_addr, 0, _SUBMIT_SM_PDU, pos, _source_addr.Length);
pos += _source_addr.Length;
_SUBMIT_SM_PDU[pos] = 0x00;
pos += 1;
_SUBMIT_SM_PDU[pos] = destinationAddressTon;
pos += 1;
_SUBMIT_SM_PDU[pos] = destinationAddressNpi;
pos += 1;
_destination_addr = Tools.ConvertStringToByteArray(Tools.GetString(destinationAddress, 20, ""));
Array.Copy(_destination_addr, 0, _SUBMIT_SM_PDU, pos, _destination_addr.Length);
pos += _destination_addr.Length;
_SUBMIT_SM_PDU[pos] = 0x00;
pos += 1;
_SUBMIT_SM_PDU[pos] = esmClass;
pos += 1;
_SUBMIT_SM_PDU[pos] = protocolId;
pos += 1;
_SUBMIT_SM_PDU[pos] = priorityFlag;
pos += 1;
_shedule_delivery_time = Tools.ConvertStringToByteArray(Tools.GetDateString(sheduleDeliveryTime));
Array.Copy(_shedule_delivery_time, 0, _SUBMIT_SM_PDU, pos, _shedule_delivery_time.Length);
pos += _shedule_delivery_time.Length;
_SUBMIT_SM_PDU[pos] = 0x00;
pos += 1;
_validity_period = Tools.ConvertStringToByteArray(Tools.GetDateString(validityPeriod));
Array.Copy(_validity_period, 0, _SUBMIT_SM_PDU, pos, _validity_period.Length);
pos += _validity_period.Length;
_SUBMIT_SM_PDU[pos] = 0x00;
pos += 1;
_SUBMIT_SM_PDU[pos] = registeredDelivery;
pos += 1;
_SUBMIT_SM_PDU[pos] = replaceIfPresentFlag;
pos += 1;
_SUBMIT_SM_PDU[pos] = dataCoding;
pos += 1;
_SUBMIT_SM_PDU[pos] = smDefaultMsgId;
pos += 1;
_sm_length = message.Length > 254 ? (byte)254 : (byte)message.Length;
_SUBMIT_SM_PDU[pos] = _sm_length;
pos += 1;
Array.Copy(message, 0, _SUBMIT_SM_PDU, pos, _sm_length);
pos += _sm_length;
Tools.CopyIntToArray(pos, _SUBMIT_SM_PDU, 0);
Send(_SUBMIT_SM_PDU, pos);
undeliveredMessages++;
return _sequence_number;
}
catch (Exception ex)
{
logMessage(LogLevels.LogExceptions, "SubmitSM | " + ex.ToString());
}
return -1;
}
Thanks a lot!!!!

Answer 1

As I can see, EasySMPP has option to split long text.
public int SendSms(String from, String to, bool splitLongText, String text, byte askDeliveryReceipt, byte esmClass, byte dataCoding)
Otherwise, smpp protocol has ability to do manually also.
Either in SAR parameters:
SAR_MSG_REF_NUM - reference, unique to all sms parts
SAR_SEGMENT_SEQNUM - sequence number (1,2,3...)
SAR_TOTAL_SEGMENTS - number of all sequences
or you can encapsulate in the beggining of the message
with UDHI set to 64
or you can set message in MESSAGE_PAYLOAD TLV and SMSC will do it for you.
Hope it helps

Answer 2

Here is the method where UDH is added.
public int SendSms(String from, String to,
bool splitLongText, String text,
byte askDeliveryReceipt,
byte esmClass, byte dataCoding)
{
int messageId = -1;
byte sourceAddressTon;
byte sourceAddressNpi;
string sourceAddress;
byte destinationAddressTon;
byte destinationAddressNpi;
string destinationAddress;
byte registeredDelivery;
byte maxLength;
sourceAddress = Tools.GetString(from, 20, "");
sourceAddressTon = getAddrTon(sourceAddress);
sourceAddressNpi = getAddrNpi(sourceAddress);
destinationAddress = Tools.GetString(to, 20, "");
destinationAddressTon = getAddrTon(destinationAddress);
destinationAddressNpi = getAddrNpi(destinationAddress);
registeredDelivery = askDeliveryReceipt;
if (dataCoding == 8)
{
// text = Tools.Endian2UTF(text);
maxLength = 70;
}
else
maxLength = 160;
if ((text.Length <= maxLength) || (splitLongText))
{
byte protocolId;
byte priorityFlag;
DateTime sheduleDeliveryTime;
DateTime validityPeriod;
byte replaceIfPresentFlag;
byte smDefaultMsgId;
// byte[] message = new byte[146];
byte[] udh = new byte[6];
string smsText = text;
byte[] message;
protocolId = 0;
priorityFlag = PriorityFlags.VeryUrgent;
sheduleDeliveryTime = DateTime.MinValue;
validityPeriod = DateTime.MinValue;
replaceIfPresentFlag =
ReplaceIfPresentFlags.DoNotReplace;
smDefaultMsgId = 0;
if (dataCoding == 8)
{
message = new byte[70];
}
else
{
message = new byte[146];
}
string[] lists = dataCoding == 8 ?
split_message_unicode(text) :
split_message_asci(text);
int count = 1;
foreach (string s in lists)
{
Array.Clear(message, 0, message.Length);
// while (smsText.Length > 0)
// {
int pos = 0;
// byte desc = Convert.ToByte('c');
byte headerLen = Convert.ToByte(05);
byte concat = Convert.ToByte(00);
byte refNo = Convert.ToByte(03);
byte sequenceNo = Convert.ToByte(03);
byte NoOfMessages = Convert.ToByte(lists.Length);
byte partNo = Convert.ToByte(count);
count++;
udh[pos] = headerLen;
pos++;
udh[pos] = concat;
pos++;
udh[pos] = refNo;
pos++;
udh[pos] = sequenceNo;
pos++;
udh[pos] = NoOfMessages;
pos++;
udh[pos] = partNo;
pos++;
Array.Copy(udh, 0, message, 0, pos);
if (dataCoding == 8)
{
int len = Tools.GetEthiopic(s).Length;
Array.Copy(Tools.GetEthiopic(s), 0, message,
pos, len);
//message =
Tools.GetEthiopic(smsText.Substring(0, smsText.Length >
maxLength ? maxLength : smsText.Length));
//message =
Encoding.UTF8.GetBytes(smsText.Substring(0, smsText.Length >
maxLength ? maxLength : smsText.Length));
}
else{
// message = Encoding.ASCII.GetBytes(s);
Array.Copy(Encoding.ASCII.GetBytes(s), 0,
message, pos, Encoding.ASCII.GetBytes(s).Length);
}
smsText = smsText.Remove(0, smsText.Length >
maxLength ? maxLength : smsText.Length);
messageId = SubmitSM(sourceAddressTon,
sourceAddressNpi, sourceAddress,
destinationAddressTon,
destinationAddressNpi, destinationAddress,
esmClass, protocolId,
priorityFlag,
sheduleDeliveryTime,
validityPeriod, registeredDelivery, replaceIfPresentFlag,
dataCoding, smDefaultMsgId,
message);
// }
}
}
else
{
byte[] data;
if (dataCoding == 8)
data = Tools.GetEthiopic(text);
//data = Encoding.UTF8.GetBytes(text);
else
data = Encoding.ASCII.GetBytes(text);
messageId = DataSM(sourceAddressTon, sourceAddressNpi,
sourceAddress,
destinationAddressTon,
destinationAddressNpi, destinationAddress,
esmClass, registeredDelivery,
dataCoding, data);
}
return messageId;
}
pass ems_class as 0x40, what you need to to is just to split your message in to parts, here is splitting method,
private string[] split_message_asci(string message)
{
int message_len = message.Length;
decimal val=(message.Length / 140m);
decimal parts = Math.Ceiling(val);
string[] strs = new string[(int)parts];
string str = string.Empty;
int interval=140;
int i =0;
int Count= 0;
while (i < message_len)
{
if (Count < (int)parts-1)
{
str = message.Substring(i, interval);
strs[Count] = str;
i += interval ;
}
else
{
str = message.Substring(i, message_len-i);
strs[Count] = str;
i += interval + 1;
}
Count++;
}
return strs;
}