_{Misrouted and Missent Messages}

^{A misrouted message is one that contains an incorrect routing instruction. This normally occurs} when the originating communications center assigns an ^{incorrect routing indicator during message header} preparation. Misrouted messages are usually not _{discovered until they reach the communications center} of the called routing indicator. Communications personnel of a tributary station in receipt of a misrouted ^{message must take the following actions:}

_{Obtain the correct routing indicator, if possible;} Apply a header change to the misrouted message and retransmit it to the correct routing indicator; and _{Originate a service message to the originating} station advising of the reroute action and the ^{correct routing indicator.}

A missent message is one that contains a correct routing indicator but is transmitted to a station other than the one represented by the routing indicator. Missent messages can be caused by an equipment _{malfunction, incorrect switching, or operator error.Communications personnel of a tributary station in} receipt of a missent message must take the following ^actions:

_{Reintroduce the message into the AUTODIN} system as a suspected duplicate (SUSDUPE) after applying a header change; and Forward a routine service message to theconnected ASC citing the complete header and_{time of receipt (TOR) and advising that the message has been protected.}

^{Suspected Duplicates}

_{When a station suspects that a message may have} been previously transmitted, but definite proof or prior transmission cannot be determined, the message should be forwarded as a suspected duplicate (SUSDUPE) by applying a header change. However, if a station ^{receives a message that is already marked} "SUSDUPE," the station should file the message if the message was previously received and delivered to the addressee. If there is no indication that the message was _{previously received and delivered, it should be forwarded.}

Stations receiving unmarked duplicate transmissions should immediately forward a routine service message to the originating station. This service message should cite the complete header format of the duplicated message, including the TOR of the original and duplicate transmissions. If the initial copy was delivered to the addressee, the station should file the ^message. _{Upon receipt of service messages concerning} duplicates, communications personnel at the originating station must take the following actions:

^{Check transmission records to determine the validity of the duplication report;} Ensure that in-station procedures are adequate to guide operating personnel in the retransmission ^{of SUSDUPE messages;}

Have maintenance personnel perform equipment checks if an equipment malfunction is suspected to be the cause of duplication; and Advise the connected ASC by routine service message if only one transmission can be accounted for.

An ASC receiving notification of a duplicate transmission should search its records to determine if the message was received in duplicate. If the message was not received in duplicate, it must be traced on a station-to-station basis to determine the point of duplication.

Magnetic Tape Messages

Magnetic tape is one of the principal media used in electronic data processing equipments (EDPEs). Magnetic tape terminal stations (MTTSs) in the AUTODIN provide for the rapid exchange of large volumes of data in a relatively short period of time. The basic mode of MTTS operation with other AUTODIN tributary stations is either full duplex or on a store-and-forward basis.

In the continental United States, terminals that have compatible equipment and circuit speeds and are connected to the same ASC may communicate directly by Hybrid AUTODIN Red Patch Service (HARPS). HARPS provides a direct subscriber-to-subscriber encrypted circuit. HARPS uses the same circuit and equipment normally used in the message-switching component of the network. Communications centers not serviced by HARPS communicate by normal message switching, which automatically performs the necessary speed, format, and code conversions.

Operating Rules

All received tape reels must be periodically dismounted and made available for delivery as scheduled by a receiving activity and system manager. A magnetic tape reel accepted by a communications facility for transmission is screened and arranged for transmission according to majority message precedence levels contained on the reel. Establishment of transmission schedules is the responsibility of the commands concerned. Prior coordination is necessary to provide for efficient use of the equipment and circuit time. Schedules are limited to 30 minutes per period.

Most facilities establish their own procedures for maintaining reel accountability and ensuring that message transmission has been accomplished. Message header and EOT printouts are finished by the message originator with each reel of tape to be transmitted. If a message cannot be transmitted, the MTTS operator returns the reel to the originator, identifying the message (or messages) that could not be sent. The originator is also provided the reason for the nontransmission, if known.

Terminal equipment should not be used to change message media format for customer convenience; for example, changing from magnetic tape to narrative records.

Operating Precautions

Communications station master records, such as history tapes and journal records, remain with the communications facility until destroyed. History tapes are labeled to prevent them from being inadvertently delivered to addressees with live traffic tapes.

Recorded information is very close to the edge of the tape. Tape-edge indentations, caused by careless tape handling, will seriously affect the accuracy of magnetic tape recordings. You should be aware that tape splices are not permitted in reels of tape used for traffic.

Message Formats

Message formats used within the AUTODIN require that each message contain a message heading, text, and EOT record. The textual material on magnetic tapes may consist of a wide variety of information recorded in either structured or nonstructured formats, depending upon the type of system.

EOT is either a single N or four consecutive Ns. The header, text, and EOT cards of magnetic tape messages are always transmitted in the AUTODIN common language code (ASCII). This is accomplished by automatic code conversion logic provided in the magnetic tape terminal.

The text of magnetic tape messages can be prepared by the EDPE system in 80-character data images, series record images, or by variable-length record images. The length of data records to be transmitted by AUTODIN may vary according to user requirements. For general transmission of data throughout the system, computerized terminals must be capable of transmitting records that contain from 18 to 1,200 characters.

Subscribers desiring to transmit messages that contain fewer than 18 or more than 1,200 characters must ensure that the addressee is capable of receiving such records prior to transmission. Typical line formats of magnetic tape message records are described in JANAP 128.

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.