[Scan-DC] New unit designators coming for DC area fire units

[Ed Tobias]

Montgomery County, Prince George's County, and Frederick
County, will be implementing the Washington Metropolitan Are
800 Regional Unit Numbering Plan. 

This should be functional by October 1st. 

The attachment (pasted below) gives an explanation of the
new unit numbering plan. 

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COG FIRE CHIEFS
REGIONAL UNIT NUMBERING PLAN
JUNE 1, 2007

REGIONAL UNIT NUMBERING OUTLINE

Unit numbering is based on the assignment of discreet
numeric jurisdictional identifiers to each major political
jurisdiction within COG. 

These assignments are as follows: 

0 - Washington, DC
1 - Arlington County
2 - City of Alexandria
3 - Metropolitan Washington Airports Authority
4 - Fairfax County
5 - Prince William County
6 - Loudoun County
7 - Montgomery County
8 - Prince George's County
9 - Frederick County

The jurisdictional identifiers are also used to identify the
trunked radio resources assigned to each jurisdiction in the
radios. 

The agencies within COG share programming across the trunked
radio systems in the region to facilitate interoperability
and these identifiers are used to facilitate identification
of, and navigation to, those resources in the mobile and
portable radios.

Apparatus/Unit Identification

These numbers are used to identify apparatus in conjunction
with unit type and the unit's assigned station number,
using the jurisdictional identifier as a prefix for the
station number.

For example:

The engine from Fairfax County Station 1 is identified as
E401.

Verbalized on the radio as "Engine Four-Oh (or
Zero)-One"

An ambulance from Montgomery County Station 12 is identified
as A712.

Verbalized on the radio as "Ambulance Seven-Twelve"

A truck from Prince George's County Station 14 is
identified as T814.

Verbalized on the radio as "Truck Eight-Fourteen"

In the event a single station has two or more units of the
same type assigned to it, an alpha suffix is added to the
unit identifier to discreetly identify each subsequent unit
of a given type assigned to that station. 

The alpha suffix of the first unit (i.e. E403-A) is silent
and will not be transmitted. 

All subsequent units will transmit their alpha designator. 

For example:

The first ambulance assigned to Montgomery County Station 41
(Ambulance 1) is identified as A741.

The second ambulance from Station 41 is identified as A741B.

This is verbalized on the radio as "Ambulance
Seven-Forty-One-Bee (or Bravo)"

The third ambulance from Station 41 is identified as A714C.

This is verbalized on the radio as "Ambulance
Seven-Forty-One-Cee (or Charlie)"

The first rescue squad assigned to Montgomery County Station
42 (Rescue 2) is identified as RS742.

This is verbalized as "Rescue Squad Seven-Forty-Two"

The second rescue squad assigned to Station 42 is identified
as RS742B.

This is verbalized as "Rescue Squad Seven-Forty-Two-Bee
(or Bravo)"

The alpha character starting point of this document is A. 

There is no reason why unit suffixes could not start at a
higher letter such as "E" if desired. 

The use of different phonetic vocalizations can be
considered to help differentiate from on-scene reports side
designation. 


Mutual Aid Responses

Unit identifiers for responses with Council of Governments
jurisdictions do not require a jurisdiction prefix such as
"Arlington", "Fairfax", or "Montgomery", as the
jurisdictional identifiers encodes the unit's home
jurisdiction, and the numbering plan prevents any
duplication of numbers across jurisdictions.
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