Bypassing the Character limit for At command AT+CMGS=

0
votes

So I've recently encountered this issue where running my AT Command on sending SMS message which returns a +CMS ERROR: 305 from my AT+CMGS= command. Upon further inspection I've discovered that there seems to be a limit to the number of characters for the message body to contain (160 char max from my testing). As a workaround I've written a code that splits the message into chunks of 160 character messages and send them as separate SMS per chunk. Management however does not like this design as it looks quite messy to be honest.

Is there any way I can get around this issue and send more than 160 characters on a single SMS message?

1
c#smsgsmat-command
Use MMS messages, convince the world to adopt a new SMS standard, or tell management to suck it up. And do some of your own research instead of asking other people to do it for you: en.wikipedia.org/wiki/Short_Message_Service#Message_size – Ray Fischer
@RayFischer Perhaps I should have been more precise with what I intend to accomplish. Our GSM phone devices could send SMS more than 160 characters but treats the excess characters as part of a separate sms and additional charges apply. At least that way, though it was treated with multiple sms charges it still comes out as a single message in the inbox. I was wondering if I could do the same with AT Commands. – Matteo
Perhaps you should follow the link I included so that you might learn something about the SMS standard – Ray Fischer

1 Answers

2
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The 160 character limit is a hard limit imposed by the protocol definition of how a phone exchanges SMS messages with the network. There is however a possibility for the sending phone to split a long message up into multiple parts that are sent (and billed) separately but marked in such a way that the receiving phone are able to concatenate them back into one large message that is presented to the user, so that there is virtual support for sending large messages (Multi-Part is the technical term).

You do not say if you are sending messages in text of PDU mode with AT+CMGS, but I am guessing text mode and as far as I know it does not support this so you have to use PDU mode (related answer).