The Echo Repeater Monitoring System (ERMS) is designed to continually monitor the health of the Sirius and XM signals and is typically installed at the output of the Echo Repeater. More specifically, the ERMS monitors Signal-to-Noise-Ratio (SNR), Bit-Error-Rate (BER), and Code Word Error Rate (CRER) statistics. When these statistics fall below pre-defined performance levels (as required by SiriusXM), the ERMS will trigger and communicate alarms via an RS-232 interface.  When statistics fall below pre-defined acceptable levels, the ERMS will generate a MAJOR alarm and will simultaneously raise a Shutdown Signal. The alarms are monitored by the Echo Repeater and a Shutdown signal will cause the Echo Repeater to turn off.

Internally, the ERMS contains a low band (LB) receiver and a high band (HB) receiver module (one for the XM signal and one for the Sirius signal). These receiver modules are quite similar to those found in vehicles and other SXM end-user devices. A built-in microprocessor continually monitors the health of the signals and reports an alarm when conditions deteriorate. The ERMS also contains a built-in event recorder which keeps a record of all alarm events as well as the date and time at which they occurred. The alarm history can be downloaded to a USB memory stick via the micro-USB connector on the front panel.