This document specifies the procedures for conventional LMR
\nsystems that permit the conveyance of digital voice, data packets,
\nand supplementary data messages over the common air interface, and
\npermit interconnect calls to a PSTN.<\/p>\n
This document does not explicitly address any procedures
\nrequired in support of any non-conventional (e.g., trunking) modes
\nof operation.<\/p>\n
A conventional LMR system is one that does not assign radio
\nchannels to SUs through the use of a control channel and
\nover-the-air signaling. It is different from a trunking LMR system
\nwhich includes some means of assigning radios to channels.<\/p>\n
A digital conventional LMR system is one which meets the minimum
\nrequirements specified in this document. Additional functions or
\nfeatures can be added as required. The operation of these
\nadditional functions is not discussed in this document, but it is
\nexpected that these are compatible with the operation as described
\nhere. Procedures covered in this standard are further restricted to
\nthe lower 2 OSI layers of the digital LMR system. Operation of the
\nencryption function, vocoder function, or user data applications is
\nnot explicitly defined here. Operation of trunking control is also
\nnot included.<\/p>\n
There are several different types of conventional LMR systems,
\ndepending on whether or not a repeater is used. These are
\ndiagrammed in Figure 1 below.<\/p>\n
For the purposes of this document, conventional LMR systems can
\nbe classified as either repeater LMR systems or direct LMR systems.
\nRepeater LMR systems make use of a full duplex fixed station that
\nis configured so that all of the signals that are received are
\nre-transmitted. Direct LMR systems transmit directly from one unit
\nto another without the assistance of any intervening repeater.
\nRadio units in an LMR system consist of mobile or portable units,
\nand fixed stations. The mobile or portable units are represented as
\nSU elements and the fixed stations are represented as FS elements
\nin Figure 1 below. The communication paths are represented as
\narrows. They are intended to show a simplex (i.e. one direction
\nonly) path. Generally, the SU is capable of operating half duplex,
\nwhich is to say that it can transmit or receive, but not both at
\nthe same time. The FS is always full duplex. Full duplex operation
\nfor portables or mobiles is not discussed for a conventional LMR
\nsystem.<\/p>\n","protected":false},"excerpt":{"rendered":"
Project 25 – Conventional Procedures<\/b><\/p>\n\n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n TIA<\/b><\/a><\/td>\n 2015<\/td>\n 92<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":690366,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2646],"product_tag":[],"class_list":{"0":"post-690356","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-tia","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/690356","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/690366"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=690356"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=690356"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=690356"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}