Decoding Federal Beacon Ray Serial Numbers - a how to guide.

stansdds

Veteran Member
#1
February 21, 2017.

Ever wonder when your Federal Beacon Ray was made? I have wondered about my collection. After what is closing in on two decades of research and data gathering, I think I have cracked the code in the serial number system. After collecting the serial numbers of Beacon Rays, especially those known to have been installed as original equipment, I found patterns relating the serial number to the year of the vehicle upon which it was installed. elightbars member Skulldigger suggested that there might also be a month of production indicated in the serial number. I had long pondered that possibility, so I went back and made a list of all the available serial numbers in my data. Sure enough, a pattern of 12 letters emerged. Federal Signal no longer has any of this information, so this has been a labor of love to try to make sense of their serial numbering system.

Is it a perfect system? I cannot be 100% certain as Federal sometimes did some weird things. I do hope you find this information helpful and perhaps those who collect sirens will be able to use my methods to decode the serial numbers on Federal's sirens.

Mike "stansdds" Stansfield

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The basic code for the Beacon Ray series produced up through early 1976 is as follows.

The first character is a numeral indicating voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The second character is a letter which, with the exception of the Model 11 Twin Beacon Ray, indicated a range of production years.

The third and fourth characters are numerals indicating the specific model of Beacon Ray. Interestingly, it seems that Federal Signal recycled some numbers for use on different Beacon Ray models.

The fifth character is a letter that likely indicates the month of manufacture unless that character is an "X". I do not know the significance of the use of an "X", but there are numerous models of the Beacon Ray line that contain an "X" before and sometimes after the year numerals and occasionally before the month letter.

The year of manufacture is indicated by the number or numbers following the fifth character.

Up through 1967, Some Model 17's will have a letter following the year numeral. Model 17/173/174/175/176's made in 1968 through early 1976 will usually have the letter "P" after the year numerals, but occasionally you may find a different letter or no suffix letter. I do not know the significance of this suffix letter.

The serial number system came to an end during 1976 and was replaced by the use of the "Series" designation.


Here are the methods to decode each model of the Beacon Ray line.
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Decoding Model 11 Twin Beacon Ray serial numbers.
Produced from 1964 through 1978.

First digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The next letter seems to have no actual function with regards to dates with the Model 11, I have seen no letter other than "B".

The next two digits indicate the specific model.
10 = Model 11 Twin Beacon Ray

The letter after the model likely indicates the month, the letters "I" and "J" are skipped for the Model 11. Federal used a slightly different lettering system, with the letters "I", "J", "L", and "O" skipped, for all other Beacon Ray models and motors marked with a date code.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
L = October
M = November
N = December

The final digit is the last digit of the year.

An example:
2B10D5 is 12VDC, Model 11, April, 1965.

In 1968 Federal began to change the serial numbering system. This newer serial number system is easier to decode with the letter before the last two digits likely being the month and last two digits are the year of production.
2B10D68 decodes to 12VDC, model 11, April, 1968

There are some model 11's that retained the older serial number system as late as 1969.
2B10H9 is 12VDC, model 11, August, 1969.

During 1976, Federal ceased using serial numbers and changed to a series designation.

Model 11, Series A1 = 1976-1977

Model 11, Series A1A = 1977-1978

Model 11, Series A3 = 1978

With the Series A1 through A3 Model 11's you may be able to get a determination of its date of manufacture by examining the drive motor. The Model 11 used three styles of motors and the motor may have a decal or an ink stamp indicating a code or a date. Dates on the motors likely will not match the serial number on the dome band badge for Model 11's made in the early 1970's, but are often dated one or two months earlier than the serial number on the dome band badge. I feel this is close enough to give insight into the production dates of the Series A1 through A3 Model 11's.

Motors used in the Model 11 are as follows.

Series 1 motor: Large, oval shaped motor case with large flat sides, model 84422B111-5, used from 1964 through 1977. Series 1 motors used in the 1970's may have a code inked onto the body of the motor. The code will consist of two characters, the first being a letter and the second being a numeral. The letter likely indicates the month and the numeral indicates the last digit of the year.

Month code letters for Series 1 motors:
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

If this code is present it will look similar to the following examples.

M.S.I. 2723 D3. This motor would be April, 1973 and was found in a Federal 11 Twin Beacon Ray, serial number 2B10E73, which would be May, 1973.
12V DC E6. This motor had the code inked on the voltage line, the D6 indicating May, 1976, in a model 11 serial number 2B10G6, which would be July, 1976.
2723 F7. This motor was in a Model 11, Series A1 and would decode to June, 1977 for the motor.

Series 2 motor: Round motor case with two flattened sides, model 84422B111-15, marked "Made in China", and were used from 1973 through 1977. These motors may have a decal with a numerical month and year date or a numerical month and year date inked onto the body of the motor.

Series 3 motor: Round motor case with two vent slots near the base of the motor, model 84422B111-25. This is the same motor that was used in the Model 24 Aerodynic. These motors could be found in the Model 11 Series A1A and Series A3. These motors usually bear a decal that contains a numerical month and year date.

The cast aluminum bulb holders used in Series A1 and A1A supported the bulb around its entire circumference. The Model 11 Series A3 introduced the use of a lighter weight cast aluminum bulb holder. This new bulb holder supported the bulb only at its top edge, where the quick change bulb holder clamp latched, and along the bottom edge of the bulb between the two hinge points of the bulb holder clamp.

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Decoding the Model 15 Junior Beacon Ray serial numbers.
Produced from 1958 through 1982.

1958 to 1976 serial numbers
The first digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The second character is a letter indicating the era of production
A = 1958-1969
B = 1970-1976

The third and fourth characters are numbers indicating the model.
10 = 15 magnetic mount, 1958-early 1961.
16 = 15 magnetic mount, 1961-1976.
11 = 15-A permanent mount 1958-early 1961.
17 = 15-A permanent mount 1961-1976.
12 = 15-B stanchion mount 1962-1974.
20 = 15-D de-mountable, most likely range of production is 1964-1972.
21 = 15-E stanchion mount, severe service cast aluminum base 1961-1982.

The letter after the model likely indicates the month, the letters "I", "J", "L", and "O" are skipped.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

The final digit indicates the last digit of the year.

Some serial number examples:
2A10F8 Decodes to 12VDC, model 15 (1958- early 1961), June, 1958.

1A16N6 Decodes to 6VDC, model 15 (1961-1968), January, 1966.

2A11A1 Decodes to 12VDC, model 15-A (1958- early 1961), January, 1961.

2A17E1 Decodes to 12VDC, model 15-A (1961-1976), May, 1961.

Some pre-1968 Junior Beacon Ray's may have the year as the last two digits of the serial number.
2A16X65 is a Model 15, produced sometime in 1965.

Beacon Rays made in 1968-1976 are easier to decode as the last two digits in the serial number indicate the year.
2B17A70 Decodes to 12VDC, model 15-A (1968-1976), January, 1970.

During 1976, Federal ceased using serial numbers and changed to a series designation. For the 15 and 15-A, Series A1 was the first series, followed by Series A1A. I do not know when the Series A1A was introduced nor what change it signified.
The 15-E seemed to start as a Series A1A and I have seen one 15-E with a serial number of 2B21B76-A1A. This appears to be a combination of serial number systems, manufacture date would be February, 1976.

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Decoding the Model 17 Beacon Ray serial numbers.
Produced from 1948 through 1985.

Two dome sizes used:
17/173 domes from 1948-1967 measured 8-1/8" across the dome's mounting flange. 174/175/176 domes were larger and measured 8-3/8" across the dome's mounting flange and the skirt had a larger hole for the larger dome. In 1968, Federal standardized the skirt and dome size with the 17 and 173 using the same skirts and domes as the 174/175/176, but some 1968 model 17's did have the smaller dome.

First digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The next letter indicates a range of years.
A,B,C,D = 1948-1954.
H,I,M = 1954-1958.
N = 1956-1963.
P = 1964-early 1968.
R = Late 1967-1976.

The next two digits indicate the specific model of the beacon.
16 = 17 and 17-H permanent mount
14,57 = 17-A stanchion mount.
22 = 17-B Quick disconnect mount
11,12 = 17-C special California model with a PAR-46 bulb in a Unity fixture attached to the beacon's skirt, "P" serial.
14 = 17-C special California model with a PAR-46 bulb in a Unity fixture attached to the beacon's skirt, "R" serial.
48,52,56,58 = 17-D De-mountable.
33 = Flange skirt.

The letter after the model likely indicates the month, the letters "I", "J", "L", and "O" are skipped.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

The final digit is the last digit of the year.

So 1C22B3 is 6VDC, model 17B, February, 1953.

"R" serial numbers are introduced in the middle of 1967. "R" serials for 1967 decode in the same fashion as the "P" serials.
2R14K7 was a Model 17-C, August, 1967 production.

The serial numbers beginning in 1968 are easier to decode as Federal simply stamped the year as the last two digits of the serial number.
So 2R57M69P is 12VDC, model 17-A, October, 1969.

Oddities in the serial numbering do occur in 1968, when you might see things like 2P16C68XP. This looks like a combination of "P" and "R" serial number systems as this would be March, 1968 production. This may be Federal Signal using up an existing supply of badges before using new badges or a transitional period in the numbering scheme.

During 1976, Federal ceased using serial numbers and switched to marking the 17 Beacon Ray as Series A1. During the Series A1 production, Federal exhausted their supply of the large diameter motor and switched to the motor used in the Model 24 Aerodynic. These motors are smaller in diamter and have two vent slots near the base of the motor. These motors may also have a label on them that contains the date for the motor.

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Decoding the Model 173 Beacon Ray serial numbers.
Produced from 1950 through 1982.

Two dome sizes used:
17/173 domes from 1948-1967 measured 8-1/8" across the dome's mounting flange. 174/175/176 domes were larger and measured 8-3/8" across the dome's mounting flange and the skirt had a larger hole for the larger dome. Federal began the sporadic use the larger dome on the Model 173 as early as 1961. In 1968, Federal standardized the dome and skirt sizes with the 17 and 173 using the same skirts and domes as the 174/175/176.

First digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The next letter indicates a range of years.
N = 1950-1959
P = 1960-early 1968.
R = Late 1967-1976.

The next two digits indicate the specific model of the beacon.
37 = 173 permanent mount, "N" and "P" serials.
78 = 173 permanent mount, "R" serial.
59 = 173-A Stanchion mount
49 = 173-D De-mountable through 1968
72 = 173-D De-mountable 1969 to 1982

The letter after the model likely indicates the month, the letters "I", "J", "L", and "O" are skipped.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

The final digit is the last digit of the year.

So 2N49F0 is 12VDC, model 173D, June, 1950.

"R" serial numbers are introduced in the middle of 1967. "R" serials for 1967 decode in the same fashion as the "P" serials.

Serial numbers beginning in 1968 are easier to decode as Federal simply stamped the year as the last two digits of the serial number.

So 2R78K75P is 12VDC, model 173, August, 1975.

During 1976, Federal ceased using serial numbers and switched to marking the 173 Beacon Ray as Series A1. During the Series A1 production, Federal exhausted their supply of the large diameter motor and switched to the motor used in the Model 24 Aerodynic. These motors are smaller in diameter and have two vent slots near the base of the motor. These motors may also have a label on them that contains the date for the motor.

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Decoding the Model 174 Super Beacon Ray serial numbers.
Produced from 1958 through 1987.

First digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The next letter indicates a range of years.
N = 1958-1959
P = 1960-early 1968
R = Late 1967-1976

The next two digits indicate the specific model of the beacon.
10 = 174 permanent mount and 174D De-mountable
11 = 174A Stanchion mount

The letter after the model likely indicates the month, the letters "I", "J", "L", and "O" are skipped.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

The final digit is the last digit of the year.

So 2P10M6 is 12VDC, model 174, October, 1966.

"R" serial numbers are introduced in the middle of 1967. "R" serials for 1967 decode in the same fashion as the "P" serials.

Serial numbers beginning in 1968 are easier to decode as Federal simply stamped the year as the last two digits of the serial number.

So 2R10A76P is 12VDC, model 174, January, 1976.

During 1976, Federal ceased using serial numbers and switched to marking the 174 Super Beacon Ray as Series A1. During the Series A1 production, Federal exhausted their supply of the large diameter motor and switched to the motor used in the Model 24 Aerodynic. These motors are smaller in diamter and have two vent slots near the base of the motor. These motors may also have a label on them that contains the date for the motor.

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Decoding the Model 175 Beacon Ray serial numbers.
Produced from 1961 through 1982.

First digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The next letter indicates a range of years.
N = 1961-1962
P = 1963- early 1968
R = Late 1967-1976

The next two digits indicate the specific model of the beacon.
10 = All 175 versions except special order, "N" and "P" serials.
15 = All 175 versions except special order, "R" serial.
11, 12, 14 = Special order 175-H for the New York City Police Department, Upward tilted bulb reduced from 45* to 15* tilt.

The letter after the model likely indicates the month, the letters "I", "J", "L", and "O" are skipped.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

The final digit is the last digit of the year.

So 1N10P1 is 6VDC, model 175, December, 1961.

"R" serial numbers are introduced in the middle of 1967. "R" serials for 1967 decode in the same fashion as the "P" serials.

Serial numbers beginning in 1968 are easier to decode as Federal simply stamped the year as the last two digits of the serial number.

So 2R15M71P is 12VDC, model 175, October, 1971.

During 1976, Federal ceased using serial numbers and switched to marking the 175 Beacon Ray as Series A1. During the Series A1 production, Federal exhausted their supply of the large diameter motor and switched to the motor used in the Model 24 Aerodynic. These motors are smaller in diameter and have two vent slots near the base of the motor. These motors may also have a label on them that contains the date for the motor.

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Decoding the Model 176 Beacon Ray serial numbers.
Produced from 1961 through 1982.

First digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The next letter indicates a range of years.
N = 1961-1962
P = 1963-early 1968
R = Late 1967-1976

The next two digits indicate the specific model of the beacon.
11 = All versions 176, "N" and "P" serials.
13 = All versions 176, "R" serial.

The letter after the model likely indicates the month, the letters "I", "J", "L", and "O" are skipped.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

The final digit is the last digit of the year.

So 2P11M6 is 12VDC, model 176, October, 1966.

"R" serial numbers are introduced in the middle of 1967. "R" serials for 1967 decode in the same fashion as the "P" serials.

Serial numbers beginning in 1968 are easier to decode as Federal simply stamped the year as the last two digits of the serial number.

So 2R13B76P is 12VDC, model 176, February, 1976.

During 1976, Federal ceased using serial numbers and switched to marking the 176 Beacon Ray as Series A1. During the Series A1 production, Federal exhausted their supply of the large diameter motor and switched to the motor used in the Model 24 Aerodynic. These motors are smaller in diamter and have two vent slots near the base of the motor. These motors may also have a label on them that contains the date for the motor.

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Last edited:

Maxim2Eng

Premium Member
Platinum Supporter
#2
WOW, Mike...just WOW!! You da man!! That's what I love about the members of this site. And I thought tracking the serial numbers of a Gibson guitar was difficult....

Note to admins: this should be pinned to its own thread!
 
#6
Thanks ! Finally that 1st letter makes sense. You truly did break the code that even Federal doesn't know.
 
OP
OP
S

stansdds

Veteran Member
#7
I just updated the month info for the models 15/17/173/174/175/176. In my initial post I had accidentally used the month codes for the motors and model 11 for all the other Beacon Ray models. This is just a correction to the month codes.
 

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