program.  This  version  is  configured  as  a  single workstation.  Version 3.0 can be configured as a multiple workstation or single workstation PCMT system   to   replace   both   the   earlier   version   1.0 MARCEMP  and  version  2.0  PCMT.  The  PCMT version 3.0 can do everything MARCEMP and PCMT version 2.0 can do—and much more. GATEGUARD SUBSYSTEM The GateGuard subsystem is an Automatic Digital Network (AUTODIN) Interface Terminal (AIT) that provides user office automation systems (OASs) a gateway to the AUTODIN system. (AUTODIN is discussed later.)  GateGuard also acts as a security guard device; hence, the name GateGuard. The GateGuard subsystem   will   eventually   allow   commands (subscribers) to interface directly with the AUTODIN system.  This  direct  interface  eliminates  the  manual handling   of   messages   by   the   servicing telecommunications center (TCC). Currently,  a  servicing  TCC  processes  (transmit  and receive)  message  traffic  from  the  AUTODIN  system  for its   subscribers.   The   GateGuard   subsystem   will eventually  eliminate  the  need  for  TCCs  because subscribers will be able to process their own messages through GateGuard. Subscribers will also be able to route messages via their local area networks (LANs) using desktop computers. The  GateGuard  system  is  comprised  of  three elements: An  AUTODIN  Gateway  Terminal  (AGT), A   gateway   communications   link   to   an Automated  Information  System  (AIS),  and A Guard Device  (GD). The AGT functions as a RIXT look-alike send-and- receive terminal connected to one of the AUTODIN subscriber   terminals,   such   as   the   LDMX, NAVCOMPARS, or PCMT. The AGT serves as the primary  AUTODIN  interface  point  for  a  single organization. The  AGT  has  software  that  will  operate  on microcomputer  systems  designed  to  be  operated  by organization admin personnel. For example, in a small command, the AGT is located in the commanding officer’s outer office and is operated by the Yeoman or secretary. The   communications   link   connecting   the AUTODIN Subscriber Terminal (AST) with the AGT passes through the Guard Device (GD). The main purpose of the GD is to assist in enforcing system security policy. Specifically, the GD serves to isolate sensitive data in the serving AST from data processed by the AGT. It does so by ensuring that each message processed  has  been  properly  encapsulated  and  assigned a security code that the AGT is cleared to process. The  serving  AST  provides  long-term  archive storage for all messages sent to or received from the AGT. When the AGT is served by an LDMX, an operator at the AGT is able to recall messages from that system automatically. The operator is  also able to identify the desired message by its originator and date- time  group,  originating  station  routing  indicator,  station serial  number,  time  of  file,  or  by  the  processing sequence number assigned to the message by that system. The following is a simplified description of how the GateGuard subsystem works: Various  offices  in  a  command  have  desktop computers  that  are  interconnected  by  the  command’s LAN. Messages drafted on any computer in the system can be stored in a central computer. These messages can be  accessed  by  any  computer  in  the  LAN.  The messages  can  then  be  reviewed  and  checked  for accuracy in format and content. When a message is released, the command sends it to the AUTODIN system via the GateGuard subsystem. At no time does the message leave the computer channels. When messages are sent to subscribers via the AUTODIN  system,  the  GateGuard  subsystem  will  be able  to  identify  messages  for  the  various  subscribers  by plain language addresses (PLAs) or routing indicators (RIs). In some cases, GateGuard will use a key word or phrase in the message text to identify the subscriber for which the message is intended. GateGuard  will  examine  each  message  for  which  it accepts  delivery  responsibility,  determine  message completeness, and determine if it contains internally consistent  security  labels.  If  GateGuard  detects  any discrepancies, the software will not allow the message to be forwarded or delivered to a diskette. However, the message can still be routed to a local printer connected to the GateGuard subsystem. 1- 4