Government telephones are intended for official
business only. Most commands permit limited, brief,
local telephone calls to be made to take care of personal
matters that cannot be conducted during off-duty hours.
However, the use of commercial long-distance services
for personal business is prohibited and is always
investigated. Detailed records of every commercial
long-distance call (telephone bills) are forwarded
monthly to each command for verification with the
long-distance phone call records.
DEFENSE SWITCHED NETWORK.The
Defense Switched Network (DSN) is a telephone
network servicing most military installations in the
continental United States and overseas. This system is
an upgraded, all-digital network that has replaced the
former Automatic Voice Network (AUTOVON). The
DSN incorporates many special features, such as
automatic callback, call forwarding, call transfer, and
call waiting. Instructions for use of the service and
special options are included in the DSN User Services
Guide, DISA Circular 310-225-1.
All telephone connections on the DSN are
connected and maintained on a precedence basis (see
table 1-1). Low precedence calls are initially connected
only if there are free circuits available between the
caller and the destination. Higher precedence calls may
initially be connected even if all circuits are in use by a
process called "preemption." When no free circuits are
found, the computer checks the precedence on calls in
progress. A lower precedence call in progress will be
terminated by the system to allow a higher precedence
call to proceed. The calling parties of the lower
precedence call hear a brief high-pitched tone on the
line just before the line goes dead to indicate that their
call has been preempted. The effectiveness of this
system depends on the proper use of the precedence
system. Each user should ensure that his or her call is
not assigned a precedence higher than that justified by
the circumstance or information involved.
Local command policy normally states that the
DSN is to be used for official calls only. Personal or
unofficial calls must never be initiated into the DSN
Telephone circuits, particularly those routed by
high frequency and microwave, are susceptible to
monitoring and interception. The DSN is not a secure
system! Users must take care and use common sense to
avoid divulging classified information. Giving hints or
talking "around" a classified subject can lead to the
compromise of classified information.
Table 1-1.DSN Telephone Network Precedence System
FLASH OVERRIDE (FO)
Takes precedence over and preempts all calls on the DSN and is not preemptible.
FO is reserved for the President of the United States, Secretary of Defense,
Chairman of the Joint Chiefs of Staff, chiefs of military services, and others as
specified by the President .
Preempts lower precedence calls and can be preempted by FLASH OVERRIDE
only. Some of the uses for FLASH are initial enemy contact, major strategic
decisions of great urgency, and presidential action notices essential to national
survival during attack or pre-attack conditions.
Preempts PRIORITY and ROUTINE calls and is reserved for calls pertaining to
situations that gravely affect the security of the United States. Examples of
IMMEDIATE calls are enemy contact, intelligence reports essential to national
security, widespread civil disturbance, and vital information concerning aircraft,
spacecraft, or missile operations.
Preempts only ROUTINE calls.
For calls requiring expeditious action or
furnishing essential information for the conduct of government operations.
Examples of PRIORITY calls are intelligence reports, movement of naval, air,
and ground forces, and important information concerning administrative military
For official government communications that require rapid transmission by
telephone. These calls do not require preferential handling.