Instruction manual

Page 38
UTY4422-001 Page 38 of 74
3.8.3 Frequency Tagging
Under normal operation, the IRD can only acquire carriers that contain frequency tags. These
tags are inserted in the COMPEL control stream at the uplink and are used for identifying the
carrier’s frequency. Tagging was mandated because, without tags the IRDs could have locked
on some other nearby (adjacent) carrier while looking for the intended carrier. The tuning can be
off by a small amount due to minor offsets in the LNB and within the receiver itself.
Traditionally, the tags have been sent at a rate of every 100 or 125 mS. The IRD supports both
single and multiple tags. The tag_site, which is part of the settings, tells the receiver which of
these 17 possible tags to use. To reduce processing overhead, the unit only looks for tags while
in the Get Tag sub-mode or when tag_testing.
3.9 DISPLAY / PUSH BUTTONS
3.9.1 Overview
The front panel consists of a 2 X 20 Display and six push buttons. Essentially all control
available through the terminal is available via the front panel. The front panel can also be used to
view a COMPEL down-loadable text message. This message is volatile and can contain up to
512 characters. The Display can be in one of the following modes:
Table 22. Display Modes
Mode Description
HOME Display shows ALARM or WARNING message (if applicable), or RF
switch position, carrier frequency, program ID and TEMP (if inserting).
Display returns to this screen after push buttons are inactive for 5 minutes
or if both ENTER and SELECT buttons are pressed simultaneously.
SN Unit Serial Number displayed for a few seconds if ENTER is pressed
while in HOME screen.
MENU Entered from Home mode. Display shows menu for each available
command group.
PARAMETER Entered from Menu mode. Display shows specific parameter associated
with command group.
EDIT Entered from Parameter mode. Display blinks edit field when in this
mode.