<s>
TSEC/KY	O
-68	O
DSVT	O
,	O
commonly	O
known	O
as	O
Digital	O
Subscriber	O
Voice	O
Terminal	O
,	O
is	O
a	O
US	O
military	O
ruggedized	B-Device
,	O
full	O
-	O
or	O
half-duplex	O
tactical	O
telephone	O
system	O
with	O
a	O
built-in	O
encryption/decryption	O
module	O
for	O
secure	O
traffic	O
.	O
</s>
<s>
The	O
KY-68	B-General_Concept
can	O
operate	O
via	O
civilian	O
and	O
military	O
switches	B-Device
in	O
either	O
encrypted	O
or	O
un-encrypted	O
mode	O
,	O
or	O
point-to-point	B-Architecture
(	O
encrypted	O
mode	O
only	O
)	O
.	O
</s>
<s>
Although	O
used	O
primarily	O
for	O
secure	O
communications	O
,	O
the	O
KY-68	B-General_Concept
can	O
also	O
transmit	O
to	O
a	O
Digital	O
Non-secure	O
Voice	O
Terminal	O
(	O
DNVT	O
)	O
.	O
</s>
<s>
A	O
local	O
switch	O
warns	O
the	O
KY-68	B-General_Concept
user	O
with	O
a	O
tone	O
signal	O
when	O
initiating	O
communication	O
with	O
a	O
non-secure	O
terminal	O
.	O
</s>
<s>
The	O
KY-68	B-General_Concept
is	O
keyed	O
using	O
an	O
Electronic	O
Transfer	O
Device	O
,	O
typically	O
either	O
a	O
KYK-13	O
or	O
AN/CYZ	O
-10	O
.	O
</s>
<s>
An	O
almost	O
identical	O
office	O
version	O
(	O
KY-78	O
)	O
features	O
the	O
same	O
electronics	O
as	O
the	O
KY-68	B-General_Concept
,	O
but	O
has	O
an	O
exterior	O
casing	O
composed	O
of	O
lighter	O
materials	O
.	O
</s>
<s>
The	O
KY-68	B-General_Concept
and	O
KY-78	O
are	O
approved	O
for	O
use	O
with	O
SECRET-classified	O
information	O
.	O
</s>
