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This can cause an apparent difference between Transmit and Receive TPL 
frequencies even when the same information has been entered into both 
fields! This should NOT cause concern, as the displayed frequency is 
the nearest encodable frequency to the one entered, and will be 
accurate within 0.5%. This difference will only occur on non-standard 
PL codes. DPL codes other than those contained in the standard table 
cannot be entered directly.
Note: A low-level hum or buzz in the received audio MAY be
experienced when the TPL code OZ (254.1 Hz) is used. This PL
code is at the high end of the sub-audible frequency range and
may be heard in the audio under certain circumstances. Use of
this code should be avoided if possible.
The default is Disabled (Default Receive Squelch is CSQ).
Transmit PL Use the UP/DOWN arrow keys to enable/disable this feature. When 
this feature is enabled, this option will turn on either Digital Private-
Line (DPL) or a Tone Private-Line (TPL) for the channel displayed in 
the channel entry. Use the UP/DOWN arrow keys to scroll through the 
choices or enter the frequency directly. Different decode and encode 
codes are allowed on the same channel.
When this option is enabled for STAR signalling, the PL signal will be 
transmitted during the transmission of RAT, Emergency, or auto-
acknowledgment on a PL channel. When enabled for MDC Signalling, 
the PL will be encoded on the PL-enabled channel during MDC 
transmission. Encoding of PL during the transmission of PTT ID is not 
controlled by this field but is always enabled on a PL-encoded channel.
When this feature is disabled, the PL signal will not be transmitted 
during STAR or MDC transmissions, except for the PTT ID 
transmission. A valid PL must be selected on the channel for this option to 
be applicable.
The default is Disabled.
PL Code (Transmit) Use the UP/DOWN arrow keys to make your selection or enter the 
desired code directly. The transmit PL code can be either a DPL code or 
a TPL code taken from the DPL/TPL tables in the Appendix. The TPL 
frequency may also be entered directly so that TPL codes not in the 
standard table are supported. When a frequency is entered directly, it 
will be encoded, and then immediately decoded and re-displayed.
In many cases, the frequency you entered may change by several tenths of a 
Hz when you exit this screen and return to it. However, due to differences 
in the algorithms for encoding and decoding TPL, the Receive TPL 
frequencies will change less often on re-display than the Transmit TPL 
frequencies.
This can cause an apparent difference between Transmit and Receive TPL 
frequencies even when the same information has been entered into both 
fields! This should NOT cause concern, as the displayed frequency is 
the nearest encodable frequency to the one entered, and will be 
accurate within 0.5%. This difference in frequency will occur only on 
non-standard PLs. DPL codes not in the standard table CANNOT be 
entered directly.