Kannel is a compact and very powerful open source WAP and SMS
gateway, used widely across the globe both for serving trillions of
short messages (SMS), WAP Push service indications and mobile
internet connectivity. Linux only. Not in active development but
well documented. Features include: Work as both Pull and Push
gateway Can handle 7-bit, 8-bit and Unicode data Delivery reports
Can handle hundreds of messages per second in average workstation
Can be used to send operator logos, ringing tones, OTA
configurations, WAP SI messages etc. but usually the message must
be created by hand Supports following SMS center protocols: CIMD
1.3, CIMD 2.0, SMPP 3.4, UCP/EMI 4.0. Also: SEMA SMS2000 OIS
protocol for SMS centers over Radiopad and X.25. Can use GMS phones
and GSM modems as pseudo SMS center Can connect various HTTP based
content gateways Can work as aggregator Local server and handset
required or can interface directly with network's SMS center