Message and Tape Reel Accountability

Magnetic tape messages prepared for transmission are limited to a maximum of 40,000 characters (five hundred 80-character data records) that include the header, text, and EOT records. The preparation of magnetic tape messages, formats, routing, contents, and sequence on tape is the responsibility of the message originator. Message and Tape Reel Accountability Each tape reel given to the MTTS operator for transmission must bear a tape label containing the following information: Reel number; Number of messages recorded on tape; Highest precedence used; Highest security classification; Date and time filed; Tape density; LMF used; Beginning and ending SSNs; and Time delivered to the MTTS operator. Each blank reel of tape furnished to the MTTS operator for mounting on the receive tape transport contains a tape label with the following information recorded in the sequence of handling: A statement that the reel is blank; Reel number; Highest classification ever recorded; Time the reel is mounted on the receive transport; Time the reel is removed from the receive transport; Time the reel is delivered to the addressee; and Number and types of message on the reel and other applicable reel information. All originated tape reels must be retained for at least 10 days. The header and EOT printouts finished the MTTS operator for both originated and terminated traffic are maintained as a station communications record for at least 30 days. Other logs recommended for MTTS operation are the master station log and the reel delivery log. The master station log reflects the current operation status of the terminal equipments and circuits. This log should also reflect equipment and circuit outages, causes of the outages, and the corrective actions initiated. The reel delivery log should indicate the reel number and the time the reel was delivered to the transmitting operator or the addressee. AUTODIN Security Required security protection must be extended to all classified traffic transmitted through the AUTODIN. The ASC automatically checks and compares the security classification stated in the header of the message against the authorized security level of the incoming circuit. Transmission of a message with a higher security level than authorized will result in the message being rejected by the ASC. In addition, an automatic system-generated service will be transmitted by the ASC to the originating station. The purpose of this service is to advise the originating station of possible security compromises. Also, the ASC automatically checks and compares the security classification contained in the header of each message against the security classification of each destination. A security mismatch occurs for each destination that does not indicate a matching security level. In the event of a security mismatch, the ASC takes the following actions: In a single-address message, the ASC rejects the message and alarms appear at the originating terminal indicating that the message needs retransmission. In a multiple-address message with at least one deliverable destination, the ASC accepts the message and delivers it to all valid destinations. For invalid routing indicators, an automatically generated service retransmits the message to the originating routing indicator and advises that the message needs retransmission. In-station operating procedures should be carefully planned and rigidly enforced to prevent inadvertent transmission of classified messages to unauthorized stations or agencies. Complete security precautions and operating rules are contained in JANAP 128. 1-12