SysManSMS Server has been tested and supports around 40 different GSM Modems. Some modems has limitations on GSM protocol support, and some are missing full character set support. The populare SysManSMS Watchdog function is supported on a few selected devices sold by SysMan. For latest updates, see Device Support List.
GSM Modem support are closely connected to the GSM Operator capabilities. Please check known GSM Operator issues, if you have problems sending/receiving SMS messages with SysManSMS Server Software.