UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
frequency transmitting equipment outside of the continental United States usually
requires approval by the Host nation. While there are some "worldwide license free"
frequencies, host nation approval can be slow and or difficult with nuances of licensed
and unlicensed equipment. Long lead times may be required for equipment that met
Host nation requirements or alternative solutions to radio frequency emitting devices
may have to be considered. Approval of radio frequency emitters should be an early
project design consideration.
6-7.4
Free-Space Optics (FSO). FSO, also called free-space photonics (FSPO),
refers to the transmission of modulated visible or infrared (IR) beams through the
atmosphere to obtain broadband communications. Most frequently, laser beams are
used. FSO operates similar to fiber optic transmission, except that information is
transmitted through space rather than a fiber optic. FSO systems can function over
distances of several kilometers, but does require a clear line-of-sight unless mirrors are
used to reflect the light energy. FSO systems offer advantages of reduced construction
cost in that fiber optic lines do not have to be installed, but there are limitations. Rain,
dust, snow, fog, or smog can block the transmission path and shutdown the network.
6-8
TECHNOLOGY COMPARISION
6-8.1
Table 6-2 provides a comparison matrix of different DTM technologies for
ESS.
6-8.2
Explanation of Table 6-2. Dedicated conductors are high-lighted for on-base
applications and T-1 lines are highlighted for interbase applications as a general guide.
Whichever method is used, initial calculations have to be made on the information
transfer (bandwidth) requirements.
6-9
ENCRYPTION
6-9.1
Encryption of ESS DTM is an evolving area with new standards under
development. Some general guidance follows.
6-9.1.1 ACS: A new emerging NFPA guide suggests that ACS inter-building
information be encrypted.
6-9.1.2 CCTV MPEG and IEEE have encryption guidelines for video transmission.
IEEE 802 is in draft version at this time. Federal Information Practices Standard 140 is
an additional reference.
Refer to Chapter 9 for additional information on tamper protection and encryption
requirements.
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