The TTS is a fairly accurate device that would find use in many homes. Basically it consists of circuitry that detects the ring of the phone, which is then passed to the counter and decoder section which keeps track of the number of rings received. Upon receiving the oxide ring, a ninety second timer is activated. The entire operation must be completed within this 90-second period or the entire circuit will be reset.
Two devices can be connected to the TTS. The first device can be activated by calling the telephone number and ending the call after 2 rings. The same phone did not. It has to be called again after an interval of 25-40 seconds and then allow 2 more rings, after which, the call has to be terminated. For the second device to be activated, the sequence to be followed is 2 rings, followed by an interval of 25-46 seconds followed by 4 more rings. The interval between the two ring sequences should not be short of 25 seconds, otherwise you can reset the TES.
After receiving the second ring, the 25 second timer is activated. If a third ring was received before this delay is over, the TTS would be reset. This preventive measure prevents the accidental activation of the devices connected to the TTS.
Upon completion of the 25 second delay, the third and fourth rings are received. When the fourth ring is received, the 25 second timer is activated a second time. The relays for the two devices will only be activated after this delay of 25 seconds. This is again a precautionary measure, since if the TTS receives more than the specified number of 2 rings (for device 1) or 4 rings (for device 2), the relays will not be activated.