User's Manual

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Transmitter Address
The unique address for each unit is preprogrammed in the Silicon Labs
radio IC during manufacturing and cannot be changed or modified by
the end user. A 16-byte pairing key is programmed into the transmitter at
the factory and is shared with the associated receiver during the pairing
process.
Button Assignments
The Keyfob is available in five button configurations. Those configurations
and the corresponding switch numbers are shown in Figure 5. The table
shows which encoder data line has been assigned to each switch. When a
button is pressed, the data line goes high, causing the corresponding data
line on the decoder to go high if the address has been learned.
S4
S2
S1
S3S5
S5
S2
S5
S4
S4
S2
S4
S1
S3
S2
Button Data Line
S1 D0
S2 D1
S3 D2
S4 D3
S5 D4
Figure 5: OTX-***-HH-KF#-MS Button Assignments
Contention Considerations
It is important to understand that only one transmitter at a time can be
activated within a reception area. While the transmitted signal consists
of encoded digital data, only one carrier of any particular frequency can
occupy airspace without contention at any given time. If two transmitters
are activated in the same area at the same time, then the signals will
interfere with each other and the decoder will not see a valid transmission,
so it will not take any action.
Battery Replacement
The transmitter utilizes a standard CR2032 lithium
button cell. In normal use, it provides 1 to 2 years of
operation. Access for replacement is accomplished
by gently prying apart the two halves of the Keyfob at
the seam (fingernails or a coin will do). Once the unit is
open, remove the battery by sliding it out from beneath
the retainer.
There may be the risk of explosion if the battery is
replaced by the wrong type. Replace it with the same
type of battery while observing the polarity shown in
Figure 6.
Assembly Diagram
Battery
Figure 6: Battery Access
Figure 7: OTX-***-HH-KF#-MS Assembly