APPLICATION
APPLICATION
N
No
ot
te
e
T
TE
EL
LE
EC
CO
OM
MS
SO
OL
LU
UT
TI
IO
ON
NS
SF
FO
OR
RT
TH
HE
E2
21
1S
ST
TC
CE
EN
NT
TU
UR
RY
Y
The K-1900-5 Touch Tone Dialer can be used in conjunction with
a handful of standard components to provide automatic dialing
from a contact closure, with an audio input to the line.
This is useful in instances where live programs or pre-recorded
announcements are to be transmitted via the public telephone
network. Used in this application, the K-1900-5 automates the
process of connecting to the remote site.
Establishing and maintaining the link to the remote site is as sim-
ple as providing continuous contact closure behind the K-1900-5.
I
In
ns
st
ta
al
ll
la
at
ti
io
on
n
Provide Dialing
and Voice from a
Contact Closure
January 21, 2000
Provide Auto Dialing (with Audio Input) from
a Contact Closure
P
Ph
ho
on
ne
e.
..
..
.7
71
15
5.
.3
38
86
6.
.8
88
86
61
1
M
Ma
ad
de
ei
in
nt
th
he
eU
U.
.S
S.
.A
A.
.
i
in
nf
fo
o@
@v
vi
ik
ki
in
ng
ge
el
le
ec
ct
tr
ro
on
ni
ic
cs
s.
.c
co
om
m
h
ht
tt
tp
p:
:/
//
/w
ww
ww
w.
.v
vi
ik
ki
in
ng
ge
el
le
ec
ct
tr
ro
on
ni
ic
cs
s.
.c
co
om
m
Due to the dynamic nature of the product design, the information contained in this document is subject to change without notice. Viking Electronics, and its affiliates and/or
subsidiaries assume no responsibility for errors and omissions contained in this information. Revisions of this document or new editions of it may be issued to incorporate
such changes.
Fax Back Doc 850
Rev 1
Printed in the U.S.A.
P
Pr
ro
od
du
uc
ct
tS
Su
up
pp
po
or
rt
tL
Li
in
ne
e.
..
..
.7
71
15
5.
.3
38
86
6.
.8
86
66
66
6F
Fa
ax
xB
Ba
ac
ck
kL
Li
in
ne
e.
..
..
.7
71
15
5.
.3
38
86
6.
.4
43
34
45
5
To
“Phone”
To
“Line”
Contact
Input
150ΩΩ1/2 Watt
Resistor
(not included)
600ΩΩ: 600ΩΩ
Transformer
(not included)
Tip Ring
Tip
Ring
Audio Input
Note: This application note is to be used in conjunction
with the K-1900-5 Technical Practice, Fax Back
Document 317.
Radio Shack Part Numbers (or equivalents):
150Ω1/2 Watt Carbon Film Resistor - #271-11009
1 : 1 Isolation Transformer 600Ω-900Ω- #273-1374
1. Program the K-1900-5 with the desired remote num-
ber as described in the K-1900-5 Technical Practice.
2. Connect the components as shown in the diagram to
the right. Note: It is recommended that the addition-
al components (resistor, transformer, etc) be mounted
to a perfboard or other suitable chassis.
3. Connect an audio source to the audio input. For opti-
mal performance, the audio source should provide a
600Ωbalanced output.
4. Closing the contact input initiates a connection with
the remote location, which will sustain for as long as
the contact remains closed. The signal at the audio
input is passed directly to the telephone line.
