User's Manual

1.8 RADIO INTERFERENCE REDUCTION.
Holatron’s design goal is to ensure that data communication errors due to radio
interference or to insufficient signal strength due to low battery, exceeding
specified range, or conductive objects in the signal path will result in failure of
intentional actuation rather than unintended actuation. This goal is achieved by
transmitting a 12 bit, 3 state, code repeatedly while a transmitter button is
depressed. Ten of those bits must match the pattern expected by the receiver,
and the other two bits select which channel (A or B) is to be actuated. Two
successive received 12 bit patterns must be identical before an actuation can
occur. Thus there is one chance in 3
20
(or a probability of .000000000287) of an
actuation occurring due to reception of a random signal. Though the probability
of unintended actuation is extremely small, it cannot be guaranteed to be zero.
Therefore, it is important that the user not enable the receiver until all persons
who might be harmed by accidental actuation are in a safe area. Additional
protection is offered by use of a bit pattern that cannot produce a match in the
receiver if a synchronization error occurs (as is the case with a “0101010101”
pattern), and by selection of 418 MHz as the operating frequency. This
frequency is sparsely used only by low power transmitters with a maximum range
of approximately 100 yards. It is not commonly used by auto security systems,
garage door openers, radio control models, cordless telephones, wireless
microphones, or two way communications equipment. Because this system
operates in the UHF region, interference from lamp dimmers, electrical
discharges, and other natural sources is also minimal.
1.9 SPECIFICATIONS.
Parameter Minimum Typical Maximum
Carrier Frequency, MHz. 417.96 418.02 418.08
Range, yards
(line-of-sight with RFLS-1RC rcvr)
60 100
Battery consumption, mA
(enabled)
(transmitting)
1.5
4.0
Low Battery Detect Threshold, Volts 8.5
Transmitter Supply Voltage 7.0