| Scrambled MMS Notifications - has anyone else seen these? |  Search
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NowSMS Support Forums ⬆ MMS & SMS Technical Discussions (unsupported) ⬆ Archive through July 24, 2007 ⬆ |
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| Author | Message | ||||
| Gary Chapman New member Username: Garychapman Post Number: 8 Registered: 06-2004 |
Hi all, We have encountered some mangled MMS Notification PDUs from carriers in Australia, Argentina and Chile. The PDUs are ok up to and including the UserDataLength, but after that it's a mess. Interestingly, any plaintext (sender, subject, content-location, transaction-id) is encoded correctly, but the UDH, field identifiers, etc. are gobbledygook. I've attached a text file containing a hex dump of such a message. Has anyone else encountered this? I'm assuming it's an SMSC bug. Cheers, Gary
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| Gary Chapman New member Username: Garychapman Post Number: 9 Registered: 06-2004 |
I've done some more investigation and realised that if you map the UserData from PC Codepage 437 to GSM (3GPP TS 27.005 Annex A has a table for this) then you almost get a "normal" MMS WSP-encoded Notification. Almost normal because there are a couple of octet values that don't seem to map properly; and when you look at the values that the WSP-encoded values map to, they do not have their MSB bit set to 1. For example: 6F 24 (CP437) maps to OC 02 (GSM) -- "x-mms-message-type=m-notification-ind" -- but it should be 8C 82. The question is, how and why is this happening? Is the modem messing things around, or is the SMSC/carrier to blame? | ||||
