Comtech EF Data’s (CEFD) SMS-651B is an automated 1:1 protection switch for high data rate satellite modems. The SMS-651B is capable of switching data rates up to 52 Mbit/s. The SMS-651B simultaneously switches data and IF. The switch can be ordered with either independent or dependent switching of modulator and demodulator. If a fault is detected in the online modulator or demodulator, a switch to the offline modem will occur. The switching will only occur if the backup is not in a faulted condition. Transmit data is buffered and sent to the backup modem by the switch to prevent false transmit fault indications. Switching is accomplished in under 100 ms. Front panel indicators show primary and backup modulator and demodulator status for easy reference.