... 75Ω loadingBT656 optionalAudio I/OCompressionG.726Audio InputMIC In or Line Input Unbalanced, 1.4Vp-p, 1VrmsAudio outputUnbalanced, 1.4Vp-p, 1VrmsAlarm ... I/OAlarm input1 External alarm inputAlarm output1 Relay output(NO) 120VAC 1A/24VDC 1APTZ controlRS485Pelco_D, Pelco_P or Transparent ProtocolsResetReset ...