For the SysManSMS Server to run stable you will need a good GSM signal. You may check the signal either in the SysManSMS HTML Status page, the Quick status, or in the SysManSMS.log. It should in average read between 15 and 31. Normally the GSM Modem will use different GSM Base stations, and automatically switch between them dependent on the traffic. For this reason the signal can vary, and you can even loose the signal for a period. If this happens, the SysManSMS Server will wait for the GSM Modem to become ready, and then reconnect. To help a pure signal situation, you can either install an external antenna (maximum 10-12m away), or you can install a serial over IP solution or switch to a LAN based modem. This can be placed anywhere on your LAN, and gives you more flexibility. If the LAN fails, the SysManSMS Modem Watchdog will send you alerts. If the SysManSMS Server disconnects from the GSM Network, you may set it up to notify you via e-mails.