2
947923
Nominal Timing and Frequency
Specifications
The timing and frequency specifications of the
Valcom V-9923B Code Call Unit are shown in
Table 1. Figure 1 is a timing chart showing the
nominal timing of a code call.
Table 1
Dial Tone Frequency
180Hz
Coded Tone Frequency
550Hz
Time Tones Broadcast
370ms
Time between tones in a sequence
500ms
Time between digits in a sequence
1.5 sec
Time between series of digits
8 sec
The Valcom V-9923B will detect 20-30Hz ringing
on the answer port. The applied ringing voltage
should be 75 to 125VAC.
DESIGN
The V-9923B provides two or three digit code
call paging via a loop start trunk port on a PABX
or by the use of a spare line button on a key
system. Figure 2 is a simplified block diagram
showing the code call unit and its connections
.
NOTE: The code call unit is designed so that
it will complete a code call sequence before
resetting and returning dial tone, even if all
parties hang up.
Application
Key systems and PABX's used in:
•
Department stores/shopping centers
•
Hospitals, nursing homes
•
Noisy locations, manufacturing plants
•
Schools,
universities
Additional Materials Required
Additional equipment is required to complete a
system when using the V-9923B. These items
are:
•
-24VDC power supply (if existing supply
inadequate or non-existent)
•
66 type connecting block
•
25 pair cable with a female amphenol
connector on one end
•
twisted pair cross connect wire
TONE ON
TONE OFF
.37 s ec.
.50 sec.
1.5 sec.
1.5 sec.
8 sec.
"3"
"1"
" 2"
"3"
"1"
SEQUENC E
BEGINS
SEQU ENCE
BEGINS
AGAIN
CONTINUES UNTIL
ANSW ERED OR
CALLING PARTY
GOES ON HOOK
FIG URE 1
