Thanks alt,
but data.Concatenation in DeliverSm data is null.

Hi Alt, This in my DeliverSm {DeliverSm, Length: 174, Status: ESME_ROK, Sequence: 0, SourceAddr: 3333333333, DestAddr: mittente} base {Inetlab.SMPP.PDU.SmppRequest<Inetlab.SMPP.PDU.DeliverSmResp>}: {DeliverSm, Length: 174, Status: ESME_ROK, Sequence: 0, SourceAddr: 3333333333, DestAddr: mittente} Ac...

I have the same problem, messageLong is 180 char this is my code : string ID = "1"; //code for send multiple message asynchronously byte[] b = Encoding.ASCII.GetBytes(ID); ISubmitSmBuilder builder = SMS.ForSubmit() .Text(messageLong) .From("mittente", AddressTON.International, AddressNPI.ISDN) .To("...