Brazil is a massive market and has always been problematic with regards to SMS delivery. Carriers either block international SMS or simply don't support them. We've tried many solutions including SS7. Nothing works well and is stable over time.
Sender ID is changed to a fixed shortcode such as 28908 or a local number to facilitate successful delivery of messages.
Outbound marketing messages are allowed in Brazil, with exceptions being adult/alcohol-related/political content.
Political content is not allowed.
Religious content is not allowed.
Unicode is not supported
Binary messages are not supported
Other features/restrictions of note:
Delivery receipts are provided for all networks, however in many instances they are network receipts instead of handset receipts.
Concatenated messages are not supported in Oi network and will be limited to 153 characters for GSM-7 (67 for UTC-16).
Concatenated messages for the rest of the networks are supported but not guaranteed.