Operations Manual

RF Technology T50 Page 37
7 SPECIFICATIONS
7.1.2 CTCSS
with channel-setting in the rack, exciter modules may be “hot-jockeyed” or used
interchangeably. This can be convenient in maintenance situations.
Channel information consists of two independent and complete sets of information,
which may differ or be the same. One set defines the parameters to be used, if the unit
is keyed up from PTT-in being “grounded”, and the other set defines the parameters to
be used if the unit is keyed up for any reason other than PTT-in being “grounded”.
The parameters that can be defined on a per channel basis are:
a) The frequency
b) The CTCSS tone (if any) to be generated
c) The delay from the initiation of the exciter to RF output being generated
(Is specified in hundredths of a second, 0 – 999)
d) The transmit tail; the length of time after the exciter is released before
transmission stops. (Is specified in seconds 0 – 999).
e) The No Tone period; a length of time after the expiry of (d) in which
transmission continues, but with no tone being generated. (Is specified in
tenths of a second, 0 –999)
f) Whether audio from Line 1, or Line 2, or both, (or neither!) is enabled,
and whether or not Pre-emphasis is required, or not, on each line, and
whether or not an extra gain pad (of 20dB) is required.
g) What Nominal Tone Deviation, and Maximum Deviation should be used
(See Tables 7 and 8)
7.1.2 CTCSS
Full EIA subtone Capability is built into the modules. The CTCSS tone can be
programmed for each channel. This means that each channel number can represent a
unique RF and tone frequency combination.
7.1.3 Channel Programming
The channel information is stored in non-volatile memory and can be programmed via
the front panel connector using a PC, and/or RF Technology software.
7.1.4 Channel Selection
Channel selection is by eight channel select lines connected to the rear panel that
mounts on the rear DB25 female connector.
A BCD active high code applied to the lines selects the required channel. This can be
supplied by pre-wiring the rack connector so that each rack position is dedicated to a
fixed channel. Alternatively, thumb-wheel switch panels are available.