and requires little maintenance. To learn how to operate an electronic calculator, you will need instruction from an experienced operator or company representative. WARNING To prevent electrical shock, never operate any calculator without ensuring that the machine is grounded. Have a qualified electrician check the grounding connec- tions. Do not use a calculator during severe electrical storms, while standing or sitting with your feet on a wet deck, or with wet hands. Care and Maintenance All calculators are precision instruments and must be protected from bumps and jars that will upset the delicate balance of their mechanism. As with other office machines, dust and dirt are big enemies. Keep your calculator clean and covered when not in use. If the machine is not operating properly, immediately unplug it. Do not attempt to repair calculators yourself. All repairs and maintenance should be done by qualified technicians or company representatives. Because of its solid state, the electronic calculator requires little maintenance other than the replacement of the projector tube. DUPLICATING MACHINES There used to be three types of duplicating or reproduction machines used throughout the Navy. The AZ was expected to be familiar with and to operate each type. The three types of duplicating machines that used to be found in maintenance activities were the photocopier, the Mimeograph, and the Ditto. The Mimeograph and the Ditto machines have since become outdated and too expensive to operate. The photocopier is widely used within all naval activities. As an AZ, you will be expected to know how to operate a photocopier. Photocopier machines provide the easiest means of reproducing copies of documents. To zerox (as it is commonly referred to) is the process of reproducing copies on a photocopier machine. This process is relatively expensive; therefore, when many copies are required, it may be advantageous to use another duplicating process, considering typing time required and other factors. There are several models of photocopier machines available, but they are alike in most respects. Manufacturer’s instruction manuals or sheets furnish operator information on their particular models. You should be properly indoctrinated by qualified personnel before operating photocopier machines. OFFICIAL CORRESPONDENCE In this section of the TRAMAN, the correct handling and routing of official mail (classified and unclassified) is discussed. The correct procedure for marking classified mail and preparing it for mailing; along with security of correspondence in the files, is discussed later. For detailed information concerning the security of classified information (which is required of all petty officers), you should refer to the latest edition of Department of the Navy Information and Personnel Security Program Regulation, OPNAVINST 5510.1. CLASSIFICATION AND SECURITY Because AZs handle mail and publications, you will need to know about classified informa- tion. You will not handle classified information unless you have been authorized to do so by the commanding officer, and then only when there is a reason for you to do so. However, you should know the categories of classified matter and security rules. Before handling of incoming and outgoing mail is discussed, several principles are described that affect all procedures concerned with docu- ments of certain categories. Transmission of Classified Matter Top Secret matter is transmitted by personal contact of the persons concerned, by the Armed Forces Courier Service, or by electric means in encrypted form. This category is never transmitted by registered mail or handled by regular routing procedures. Secret and Confidential matter may be transmitted by registered mail or by any of the means approved for Top Secret. The AZ will be concerned chiefly with its transmittal by registered mail. Material designated as Confidential requires modified handling and may be sent by ordinary 2-13