Both the INT-A030 and INT-A031 are intended for telephone line data monitoring. Both units utilize an RF link, with a transmission level of 30 mW and 15 mW respectively.
INT-A030 offers serial connection for telephone line monitoring. The transmission level is 30 mW.
INT-A031 offers 15 mW transmission level and provides serial connection for telephone line monitoring. It also offers Delta modulation for encryption to reduce the chance of the signal being intercepted.
These transmitters remain in standby mode as long as the telephone receiver is on the hook. When the receiver is lifted, the transmitter engages and becomes active. No interference will be created by the transmitter when in operation, regardless of connection location or polarity. Both transmitters offer unlimited operation time, as power is supplied from the telephone line. Note that an audio receiver is necessary.