User's Manual

Operation
RFI-148 & RFI-900 High Output Power Paging Transmitters User Manual Page 31 of 134
Standard 2-level Flex™ requires that FLEX-2 is selected with Data Invert -> Inverted.
Use of the H- or L- bit is configurable via Encoder Interface → 2-Level Data. The configurability of the 2-
level data pin was introduced in firmware 4.5; versions prior to this operate with L-bit as the 2-level data pin.
4.4.4 4-Level Deviation Mapping
When using 4-level FSK i.e. FLEX-4 or Custom 4-level is selected in Profiles -> Paging Protocol, the
deviation with respect to the H and L bits is outlined in Table 10 below. Note that two interpretations of the
H-bit/L-bit are available, denoted as Legacy and Normal and configurable via Encoder Interface → 4-Level
Operation. The Legacy/Normal operation was introduced in firmware 4.0. Firmware versions prior to this
operate implicitly in Legacy mode.
L-Bit
(MSB)
H-bit
(LSB)
Deviation from Carrier (Hz)
Normal
Inverted
Normal
Legacy
Normal
Legacy
N/C
N/C
+
𝐹
𝑑
3
+
𝐹
𝑑
3
−𝐹
𝑑
−𝐹
𝑑
N/C
Gnd
+ 𝐹
𝑑
−
𝐹
𝑑
3
−
𝐹
𝑑
3
+ 𝐹
𝑑
Gnd
N/C
−
𝐹
𝑑
3
+ 𝐹
𝑑
+ 𝐹
𝑑
−
𝐹
𝑑
3
Gnd
Gnd
−𝐹
𝑑
−𝐹
𝑑
+
𝐹
𝑑
3
+
𝐹
𝑑
3
Table 10: 4-level deviation frequency offsets
Where 𝐹
𝑑
is the deviation frequency in Hz.
Standard 4-level Flex™ requires that FLEX-4 is selected with Data Invert -> Normal and 4-Level Operation
-> Normal. With this configuration the L-bit is kept the MSB and the H-bit is the LSB.
4.4.5 FLEX™ Operation
Standard 2 and 4 level FLEX™ operation can be implemented in several ways. The first is as described
previously in 4.4.3 and 4.4.4. The alternate method is as follows:
1. The LIU connector is wired with the L-bit as the MSB and the H-bit as the LSB.
2. The FLEX-4 protocol is selected by Profiles -> Paging Protocol -> FLEX-4 with Data Invert ->
Normal and 4-Level Operation -> Normal.
Encoder Interface -> 4-Level Operation