We do not offer any similar devices. Such a device, however, could be constructed by the user and might consist of a 20 or 30 Vac or Vdc SPST NO relay (Single Pole Single Throw Normally Open contact relay) that is operated by the line voltage being monitored. When the relay is energized (when the 20 to 30 Vac or Vdc is supplied to the relay control coil), the contacts on the relay could carry a 5 Vdc signal from the 5 V on the data logger to one of the control ports of the data logger. This signal would then indicate to the data logger that the ac voltage is present.