SINGLE AUDIO SYSTEM (SAS)
The Single Audio System (SAS) was developed to
fulfill the requirement for an integrated secure/non-
secure shipboard voice communications system. It
consists of telephone sets, voice-signal switching de-
vices, various control devices, and field changes to
existing equipment, in conjunction with other ele-
ments of the overall shipboard radio communications
system. The SAS is essentially the baseband (AM
and/or FM ) hf, vhf, or uhf audio subset of the ship-
board exterior communications system. It incorporates
voice communications circuits, user control over the
operating mode (both secure and nonsecure), and
various degrees of operator control over voice circuit
selection. Figure 2-13 shows the major equipment
groups, subsystems, and their interrelationship.
There are two versions of SAS: an automated
system (ASAS) and a manual system (MSAS). The
voice switching equipment and means provided for
user control over circuit selection are the two primary
differences. Information in this section applies to both
ASAS and MSAS, unless otherwise specified.
There is no specific list of equipment that makeup
every SAS installation. There can be different types
and quantities of equipment in each of the groups
identified in figure 2-13. Equipment types and
quantities are dictated by the communications
requirements of individual ships and ship classes. The
publication, Operation and Maintenance Instructions,
Single Audio System, NAVELEX EE109-CA-OMI-
010/El10 SAS, identifies, in tables 1-1 and 1-2, the
SAS equipment commonly used in the fleet.
The SAS incorporates basic capabilities for setting
up and operating voice communications circuits. An
SAS installation provides the unique capability to
communicate in a secure or nonsecure mode, at the
discretion of the operator, from a single telephone or
NTDS device. This single audio interface with various
crypto or plain subsystems is the essence of the SAS.
The SAS provides the following options:
The user can select the transmit operating mode
except for FLTSATCOM secure voice and
The system can notify the user of the transmit
operating mode selected, both visually and with
The system can notify the user by visual indica-
tion if the voice station equipment is not con-
nected to a crypto or plain subsystem.
The system can notify the user of any incoming
secure (CIPHER) signals by both visual and
audio indications except for the FLTSATCOM
secure voice configuration.
The user can select a voice channel and have it
In addition to these capabilities, the ASAS version
has the following features:
A processor controlled, programmable voice
Figure 2-13.Single Audio System (SAS).