Hi, To quote from a previous post and give credit to Andreas Fink:
Here's the exact calculation of the PDU splitting borders. >> >> On the wire and in the air, a SMS PDU always contains a maximum of >> 140 octets. >> Thats why you can pack 140*8/7 = 160 characters into an SMS. >> >> If a UDH header is used (udh indicator bit is set), then the >> beginning of the SMS-PDU contains the UDH (universal data header). >> The UDH is 6 octets for a splitted text sms. This leaves us with >> 134 octets remaining. >> 134 octets are 1072 bits. in 1072 bits you can pack 153 septets >> and you are left over with one spare bit. >> This is where the 153 character limits for split SMS comes from. I also thought it was 154, but after more research it turns out to be 153 because of the extra bit. See: http://www.kannel.org/pipermail/devel/2007-February/000839.html Rgds --------------------------------------------------------- Date: Wed, 5 Aug 2009 08:11:56 -0500 From: Alvaro Cornejo <[email protected]> Subject: Re: concatenation and split count [cross post from users list] To: [email protected] Cc: [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1 Hi Konstantin Search the list, some time ago there were a discussion about this issue; however I do not remember the end of it... In any case, you can calculate the number of message parts before hand. If I do recall correctly, udh for splitig takes the equivalent of 6 chars in an 7 bit charset so you will need to calculate how many 154 chars messages your original message will get splitted into. For other charsets, you will need to adjust accordingly but the udh lenght will remain the same Hope helps Alvaro |--------------------------------------------------------------------------- --------------------------------------| Env?e y Reciba Datos y mensajes de Texto (SMS) hacia y desde cualquier celular y Nextel en el Per?, M?xico y en mas de 180 paises. Use aplicaciones 2 vias via SMS y GPRS online Visitenos en www.perusms.NET www.smsglobal.com.mx y www.pravcom.com
