signal upon which security integrity of the system is dependent.
This tolerance will be applicable for frequencies above 100 Hz.
2.4.13.2
Control Communicator Hardwire Link
The control communicator to central alarm reporting processor
communications link shall operate over a maximum of [2] [4] [_____]
standard voice grade telephone leased or proprietary lines. Digital
communicator shall conform to UL 1635. The link shall be capable of
operating half duplex over a Type 3002 data transmission pair and shall be
capable of modular expansion. Telephone lines will be provided by the
Government. Coordinate and check out system operation. General
characteristics and telephone line service shall be as follows:
a.
Connections:
Two- or four-wire
b.
Impedance at 1000 Hz:
600 ohms
c.
Transmitting level:
0 to 12 dBm
d.
Transmitting level adjustment:
3 dB increments
e.
Type:
Data
f.
Direction:
Two-way alternate (half duplex)
g.
Maximum speed:
[1.2] [5.12] [10.24] [_____] kilobaud
h.
Maximum loss at 1000 Hz:
33 dB.
2.4.13.3
Radio Frequency Link
**************************************************************************
NOTE: Radio frequency links may not be allowed on
some Government facilities. Recommended usage for
RF links is as backup to hardwire links or at a
remote location lacking telephone lines. OPNAV
Instruction 2400.20E requires that funds shall not
be obligated for procurement of radio equipment
until frequency allocation authority has been
obtained. As soon as possible, but no later than
schematic design, the designer shall contact the
area radio frequency coordinator (usually the base
radio officer) to determine the availability of
radio frequencies and to ensure that the using
activity submits a DD Form 1494, Application for
Frequency Allocation, for a Stage 1 ("Conceptual
Development") allocation (see DD Form 1494
Preparation Guide). Stage 1 allocation authority
(i.e., approval) must be obtained prior to
advertisement of the contract.
The 138 to 150.8 MHz band is the preferred range
since specific frequencies in this range are
reserved for DOD use. Frequencies in the 162 to 174
MHz and 450 to 470 MHz bands are shared with other
users on a first-come, first-serve basis. To avoid
potential contract delays, the frequency assignment
should be included in the specification when
SECTION 13702N
Page 25
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