L.A. County Fire Department S.C.U. (dispatch) tone archive

Dedicated to the fans of the television show "Emergency"

Last Update - 9/22/2014

• For years before starting this page in the mid-2000's, I had noticed that there was no archive on the Internet for the actual tones used for dispatching by the L.A. County FD during the 1970's other then a few WAV files taken from the Emergency television show. The actual dispatch tones (called SCU tones) are highly popular, however the information has not been available until now for a archival quality reproduction of the 1970's tones. The 1990's tones are now available on another webpage, these tones were taken directly off one of the actual Zetron encoders used by L.A. County. To listen to or download the 1990's tones, point your browser to http://www.lacountyfire.com and follow the menus from there. These are good quality tones, however they are representative of the end life of the SCU system in the last few years it was in service. If you listen to both sets of tones, you will see the 1970's tones DO sound different, even though it's the same alerting methodology being used.

• I obtained the actual L.A. County FD tone listing for the station tones (the tones in-use at the time of the system's termination in 1997) from the L.A. County Fire Museum Association. Just as a sidenote on how this project started, I acquired an actual Motorola T1251A encoder in 2002 (first unit pictured on this page) and I have one day the goal of restoring the unit. It's pictured here in it's current condition. It just happened to be a tone series "Z" unit, and when restoration is complete I thought it would be neat to be able to demo the unit for visitors with actual L.A. County tones.

• To use the encoder, the dispatcher would depress two of the alpha buttons in the first row, two of the alpha buttons in the second row, then the "code start" key. This is why QC1 always has a four letter code (example - KPGJ) instead of a numerical code. Also you can invert the code, KPGJ is the same code as PKJG! Same buttons get pushed either way...

• Additionally, just some trivia, during the Emergency episodes there were different tones sounded for "Engine" or "Station 51" and for "Squad 51". The tone that was used for the engine/station was the tone for Station 22. The tone that was used for the Squad is the tone for Station 50 (which at the time was the tone assigned to Station 32). The SCU units were becoming difficult to maintain, accordingly as equipment would break or become unusable, tones were sometimes "reused" for other stations when they could be reassigned. Thanks to Al "Action" Jackson, L.A. County FD Communications for that neat piece of information!!

• Here are some shots of the same style paging equipment that was used by LA County FD. To page either one station or a series of stations, the dispatcher would depress button(s) on the "preselector" console that is preset to activate each of the individual stations. The preselector hooks into the encoder (tone generator) via a big plug and multi-conductor cable. The preselector console saved a lot of time in punching up the four letter code for each station as they could be pre-programmed into the unit. Multiple stations could be alerted quite easily using the preselector console. Also this front panel was available in LA as a backup should it be necessary to manually alert a station, although mostly the dispatcher used the preselector. On another website there is a picture of Mr. Sam Lanier (who was the dispatcher in all the Emergency shows), the picture shows Mr. Lanier dispatching in the late 1960's, and in the background is one of these encoders.

• The following pictures came courtesy of Tim Bell, Montgomery Co MD, FD and Mr. Larry Gaddis (pictures used with permission). His FD (circa 1981) also used QC1 alerting. One day he ran into the encoding equipment pictured here at a hamfest which he purchased & saved. This equipment is now preserved in a private collection. This is the ONLY example I have ever seen of the preselector console except for video from an Emergency episode. I'm glad someone saved one for posterity!!

• The following pictures came courtesy of "J.B., an old LA County Fire Buff" (pictures used with permission) and represent a view of the LA County Fire communications center in early 1982. One shot clearly shows the Quik-Call encoding setup. Looks like the dispatcher was caught in the middle of his lunch hour, I can remember back how many times groups & people touring came through my dispatch center and I had my lunch spread out. It's interesting that in the shot of the encoders that there is also apparently a GE Type 99 encoder installed with the Quik-Call gear. I found out from another website viewer that this encoder was used to page the on-duty Batallion Chief. Interesting mix of technology...

• To reproduce the station tones for this page, I used a Zetron Model 25 encoder played through a radio (RF) control station. The tones were then recorded directly into a computer "off-air" from a scanner. The tones were then digitized into WAV format using Goldwave 4.26.

• A few facts on the tones listed here - LA County used the Motorola Quik-Call I dispatch encoding method until 1997. The original Quik-Call encoders were replaced sometime in the late 1980's with the Zetron Model 25. Motorola Quik-Call encoders were dependent on vacuum tubes and "Vibra-sender" reeds and were a pain on the maintenance end (see above). I used Goldwave 4.26 (a wonderful shareware sound file editor) to duplicate both the tone timing & tone intervals, these parameters were set into the Model 25 used to reproduce the tones. Also it's been reliably reported that L.A. County transmitted the Quik-Call tones during the 1970's at between 6 and 8 khz deviation. Accordingly the tones sound rather unique, and in order to assure an accurate reproduction you must slightly overdrive the tones for maximum effect. Also, another website user wrote me that "You've no doubt noticed that the audio signal which the (encoder) produces sounds different than that produced by any other QC tone generator. The reason is that all 12 reeds of the (encoder) vibrate at a low level (what Motorola refers to as "bleed through") during a 4-tone transmittal, giving a multi-chord-like sound. In fact, those 12 reeds vibrate continuously as soon as you power up the encoder, but the speaker is muted so you don't readily hear them."

• I've also had a few requests for the Zetron alert tones as produced by the Model 25. Even though it's not really QC1 related, L.A. County DID use Model 25's so I am including these selectable alert tones on the page. I can't tell you how they were used or if they were even used at all during LA's dispatch operations, just that they were available in the encoder if the dispatcher wanted to use them and knew how to access the codes to activate them.

• L.A. County used Tone Group "Z" within Quik-Call I. Tone timing (taken from a series of multiple WAV files sent during an "Emergency" episode and later analyzed) is set as follows: Tone A/B on - 800 ms. Gap - 175 ms. Tone C/D on - 850 ms. Delay until next call transmitted when calls "stacked" - 750 ms. This exactly duplicates the tone timing from the old L.A. County Quik-Call I encoding setup used during the "Emergency" TV episodes. 5 seconds on all group calls.

• You will notice a four group letter code after the station number, this is the actual Quik-Call I tone code for the station if you want to have a stab at creating your own tones. I was told by one LA County person that some of my tone codes were inverted (example - PKPK vs. KPKP group call). I will correct these as I find them. However, it doesn't matter for the tones themselves as it's the exact SAME TONE!!! The only way to get the code list exactly correct is to see a copy of the 1970's tone list in the correct QC1 format so I know how LA listed the tones. If anyone out there has a copy of the list, I pledge that I will modify my tone listing in the correct sequence, however I need the source material to do it. Irregardless, they are the same tones no matter what sequence they are listed in. Somewhere I read that LA County listed their station tones like this example (Station 22 FZPZ-GZKZ) reflecting the Group Z tone designators. This is currently unverified. I did find out the correct way to list the tone codes is in ascending order so I have edited the listing slightly to accommodate this.

• Over the years, I've had requests for the actual tone frequencies that correspond to the letter codes. I've recently modified the page (09/14) and the actual tone frequencies are now listed a little bit further down in the QC1 to Selcal translation table. It's a little easier to read.

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• There are no restrictions on this data that I am aware of. Since this is an obsolete, discontinued paging system these tones are no longer in use in L.A. County. Please note I would never publish active frequency/tone lists on anyone's public safety paging system!. This system is still actively used in the airline industry as "SELCAL", allowing individual call of airplanes by ground stations. More information on that immediately below. Also I disclaim any liability for any inaccuracies found on this page, this information is based on archival records and is provided to you as it was provided to me. Remember these are the tones that were in use in 1997, some of the stations may have changed tones during the many years the system was in use.