An electromagnetic relay, which is excellent in assemblability and includes an indicator which can be operated smoothly, is provided. The provider agent receives event messages from the telephony card indicating on-hook events, off-hook events, and digit events. Further, the system comprises means for switching the first communications device to and from sleep mode in response to receiving the wake up signal. Each of the jaw members also includes an electrically conductive sealing plate for communicating electrosurgical energy through tissue held therebetween. Finally, a second stage circuit in communication with the first stage circuit is configured to derive an optical signal strength of the optical signal based upon the differential output received from the first stage circuit.