May 7th 2000 NOTE This file has been updated by Lindsay Blanton to include new discriminator output locations. This article/file is for the benefit of all. Orignial File by: (c) 1998 (All Rights Reserved) by: Bill Cheek and -COMMtronics Engineering- This file is for personal use only and may NOT be placed on a CD-ROM nor any other media that conveys, stores, or transports for any monetary cost including shipping & handling, without expressed permission of the author. This file can only be given away, absolutely free of charge, no strings attached. If given away, it MUST be conveyed intact, word-for-word with no editing, additions or deletions, except as may be authorized in writing by the author. -Bill Cheek- Original Author NOTE: This Frequently-Asked-Questions (FAQ) file or article is one of a series of FAQs that I regularly publish. The complete list of FAQs is given below. If this one doesn't answer your questions, try one or more of the following additional FAQs: 1. Scanner Modifications FAQ: SCANMODS.FAQ 2. Scanner Data Decoder FAQ: SCANDATA.FAQ <--- This FAQ 3. Scanner Performance FAQ: SCANPERF.FAQ 4. Scanner S-Meter FAQ: SCANSMTR.FAQ 5. Scanner Radios FAQ: SCANRADS.FAQ 6. Administrative FAQ: ADMIN.FAQ You can download the latest of any of my FAQs directly from my FTP site as follows: ftp://ftp.cts.com/pub/bcheek ============================================= Bill Cheek's Scanner Data Decoding Frequently Asked Questions File ============================================= Contents ========= 01: What is a 'Discriminator Output' and 'baseband audio'? 02: How can I find the Discriminator Output in my scanner? 03: How do I connect to the Discriminator Output? 04: How do I build a decoder interface circuit? 05: So how do I decode digital data from the airwaves? 06: How can I decode CTCSS, DPL, and DTMF from the airwaves? 07: Is it possible to "TrunkTrack" without a TrunkTracker? Questions and Answers ========================================================== 01: What is a 'Discriminator Output' and 'baseband audio'? There is a growing interest in tapping the baseband audio out of various scanners for decoding of a variety of esoteric signals, including CTCSS, SCA, FSK, RTTY, FAX, Pager data, and trunked system control data, etc. By and large, such signals cannot be taken from TAPE REC jacks, headphone jacks, and EXT SPEAKER jacks because of the voice-band filters that are between the signal source and these output jacks. Therefore, it is necessary to tap the "baseband audio" directly at the output of the discriminator chip for your scanner. =============================================================== 02: How can I find the Discriminator Output in my scanner? Table 1 shows a list of scanners, the discriminator chip(s) used in the scanner, circuit symbols of those chips, and the baseband audio (discriminator output) pin. If your scanner isn't listed in Table 1, then refer to Table 2 to find its discriminator chip. The chips listed in Table 2 are all known Discriminators used in scanners and wide coverage receivers. Between Tables 1 and 2, you should be able to find the discriminator and its output pin for any reasonably modern scanner. Corrections and additions to these lists are requested. See my email and other addresses at the end of this file. TABLE 1: SCANNER DISCRIMINATOR CHIP PINS OF INTEREST Updated 07/5/98 DISCR/DET CKT BASEBAND SCANNER CHIP TYPE SYMBOL AUDIO PIN ============== ============== ======= ========= unknown MPS5071 n/a 9 AR-1000 TA-7787AF IC-4 9 AR-2002 MC-3357P IC-4 9 AR-2500 TA-7761P IC-13 9 AR-3000 MC-3357P ? 9 AR-800 MC-3361N IC-200 9 AR-900 MC-3361N IC-201 9 AR-950 MC-3361N IC-201 9 AR-8000 NFM TK10489M or-85M U1 11 AR-8000 WFM/AM TA7792F U3 8 BC-80XLT MC3361B0 IC-101 9 BC-100XL MC-3359P IC-1 10 BC-100XLT TK-10421M-2 IC-401 11 BC-140XLT MC-3359P IC-1 10 * BC-200XLT TK-10421M-2 IC-401 11 BC-205XLT TK-10421M-2 IC-401 11 BC-235XLT MC3361CDR2 IC-2 9 BC-250 ? IC-3 9 BC-2500XLT TK-10930VTL IC-201 12-FM 13-AM BC-3000 NFM/AM TK-10930V IC-202 12-NFM 13-AM BC-3000 WFM TK-10489M IC-203 11 BC-350A NJM-3359D-A IC-3 10 BC-400XLT NJM-3359D-A IC-1 10 BC-560XLT NJM-3359D-A IC-1 10 BC-700A NJM-3359D-A IC-3 10 BC-760XLT NJM-3359D-A IC-2 10 BC-800XLT MC-3359P IC-1 10 BC-235XLT MC3361CDR2 IC-2 9 * BC-8500XLT MC-3361BP IC-9 9 BC-855XLT TK-10421M-2 IC-401 11 BC-890XLT NJM-3359D-A IC-3 10 BC-895XLT MC13371 IC-3 9 * BC-950XLT NJM-3359D-A IC-2 10 BC-9000XLT MC3361B0 IC-8 9 BC-9000XLT WFM TK10489-MTL IC-9 11 BC-9000XLT AM LA1600A IC7 8 or 9 (?) BCT-7 MC3361BD IC-2 9 HX-1000 TK-10420 U-201 9 MR-8100 NJM-3359D-A IC-3 10 MX-5000 MC-3357P IC-4 9 MX-7000 MC-3357P IC-4 9 Maxtrac (Mot) 79G05 QLMD9035 6 (Behind the channel-up button) PRO-2002 MC-3357P IC-101 9 PRO-2003 MC-3357P IC-104 9 PRO-2004 NFM/AM TK-10420 IC-2 9 (TP4) PRO-2004 WFM KB4419A IC-1 6 (TP3) PRO-2005 NFM/AM TK-10420 IC-2 9 (TP2) PRO-2005 WFM KA2243N/HA12413 IC-1 10 (TP1) PRO-2006 NFM/AM TK-10420 IC-2 9 (TP2) PRO-2006 WFM KA2243N/HA12413 IC-1 10 (TP1) PRO-2011 TK-10420 IC-1 9 PRO-2020 MC-3357P IC-101 9 PRO-2021 TK-10420 IC-2 9 PRO-2022 MC-3361N IC-1 9 PRO-2023 NJM-3359D-A ? 10 PRO-2024 MC-3361N IC-2 9 PRO-2025 NJM-3359D-A IC-1 10 PRO-2026 NJM-3359D-A IC-7 10 PRO-2027 MC-3361N IC-2 9 PRO-2028 NJM-3359D-A IC-2 10 PRO-2030 NJM-3359D-A IC-3 10 PRO-2032 MC-3361 IC-2 9 (TP5) PRO-2035 NFM/AM TK-10420 IC-2 9 (TP2) PRO-2035 WFM KA2243N/HA12413 IC-1 10 (TP1) PRO-2039 NFM KA3361 IC-2 ( use TP6) PRO-2040 MC3361BP IC-2 9 PRO-2041 MC3361N IC-301 9 * PRO-2042 NFM/AM TK-10420 IC-2 9 (TP2) PRO-2042 WFM KA2243N/HA12413 IC-1 10 (TP1) PRO-2050 MC3361CDR2 IC-2 9 * PRO-23 MC-3361BD IC-1 9 PRO-26 NFM/AM TK-10930V IC-14 12-NFM 13-AM PRO-26 WFM TK-10489M IC-16 11 PRO-31 TK-10420 IC-1 9 PRO-32 TK-10420 IC-101 9 PRO-34 TK-10420 IC-101 9 PRO-35 TK-10421M-2 IC-401 11 PRO-36 TK-10420 IC-101 9 PRO-37 TK-10420 IC-101 9 (TP103) PRO-38 MC-3359P IC-1 10 PRO-39 MC-3361N IC-201 9 PRO-41 MC-3359P IC-1 10 PRO-42 MC-3361N IC-2 9 PRO-43 TK-10427/-10420 IC-301 9 PRO-44 MC-3361N IC-201 9 PRO-46 TK-10421M-3LT IC-401 11 PRO-49 MC3361BP IC-2 9 PRO-51 MC-3361BD IC-1 9 PRO-60 ? IC-301 9 PRO-62 KA3361 IC-301 9 * PRO-64 MC3361N IC-301 9 PRO-66 MC3361N IC-2 9 (TP3) * PRO-90 MC3361CDR2 IC-2 9 Icom R-1 NFM TK-10487 DET-A IC-1 11 Icom R-1 WFM TA-7787AF DET-B IC-1 9 Icom R100 NFM MC3357P 9 (Near Bottom of radio) Icom R7100 Said to be "top of R230 on main PCB" * R-1600 NJM-3359D-A IC-2 10 R-4030 TK-10421M-2 IC-401 11 SR-15 TK-10421D-2 IC-1 9 StandardCCR708A TK-10420D Q602 9 * TurboScan 2 3130-6056-502 U-201 10 or 16 WiNRADiO NFM MC-3372D U2 9 TP20 WiNRADiO AM/WFM TA-7640AP U5 9 TP29 WiNRADiO SSB LM324M U6 1 Yaesu FRG-9600 MC-3357P ? 9 * ===================================================== * Not personally verified by me TABLE 2 DISCRIM OUTPUT CHIP PIN ========= ====== KA3361 9 MC13371 9 MC3357P 9 MC3359P 10 MC3361 9 MC3372D 9 MPS5071 9 NJM3359DA 10 TA7640AP 9 TA7761P 9 TA7787AF 9 TA7792F 8 TK10420 9 TK10421D 9 TK10421M 11 TK10427 9 TK10485M 11 TK10487 11 TK10489M 11 TK10930V 12 HA12413 9 WFM Only KA2243N 9 WFM Only KB4419A 6 WFM Only Once you locate the discriminator in your scanner, you have to make its output conveniently available on the exterior chassis, much like a headphone or tape recorder jack. Figure 1 below shows how to determine the pin numbering system for most integrated circuits. Looking at the marking side of the chip, there is either a notch or nook at one end, and/or an embedded "dot" off to one side at one end. The notch, nook, or dot signifies the end that starts with Pin #1 and ends with whatever the highest numbered pin happens to be. Most IC's have 8, 14, 16, or 18 pins. FIGURE 1 TYPICAL IC CHIP PINOUT 14 13 12 11 10 9 8 | | | | | | | +---------------------+ | | | TOP VIEW | Notch \ LABEL | / Dot SIDE | | O | | | +---------------------+ | | | | | | | 1 2 3 4 5 6 7 ============================================================== 03: How do I connect to the Discriminator Output? HOOKUP PROCEDURE ================ If you need the raw Discriminator baseband audio signal for external purposes, the best way to access it is via a jack installed in a convenient, unobtrusive location on the scanner. 1A BASE SCANNERS: Install an RCA or other jack in a desired place on the scanner's external case, typically the rear panel. 1B HANDHELD SCANNERS: If you can find the space, use a standard monaural 1/8" phone jack or a 3/32" mini phone jack. Some scanners are so cramped inside that even these won't fit. In that case a strip of 3 pinline sockets can be melted into the plastic case and wires soldered to the inside protrusions. The middle pinline socket is not connected to anything; it's just there as strength and support for the pinline plug you make, with the shield ground soldered to one end and the audio- center soldered to the other end: GND---o o o---NFM DSCR (audio) "Break-apart" pinline plugs/sockets are available from Mouser, DigiKey, and Hosfelt. These little puppies are good for a lot of hacker needs, so get a supply! 2. Connect the shell or outer frame part of the jack to scanner chassis ground. (Use one end socket for pinline connections) 3. Connect the (+) leg of a 1.0-uF to 4.7-uF tantalum capacitor to the Discriminator output Pin. (Capacitor should be tantalum, but can vary in value from 1.0-uF to 10-uF at a voltage rating of 16-35 vdc.) 4. Connect the center conductor of a shielded coax (RG-174, etc) or shielded mic cable to the (-) leg of the capacitor. NOTE: if the distance from the NFM tap to the jack is less than 3", then a single unshielded hookup wire will do fine. 5. Connect the shield of the cable at this end to a nearby PCB ground trace or spot. 6. Connect the center conductor of the other end of this cable (or single hookup wire) to the center or hot lug of the jack. 7. Connect the shield of the cable at that end to the ground lug of the jack. 8. Fabricate or buy a shielded patch cable with one end to mate with the new jack on the rear of the scanner at that end....and the other end to mate with whatever jack is on the tape recorder, processor, decoder, or whatever device is to be connected at the other end. Now you are ready to connect a data decoder interface to the baseband audio output jack. ================================================================= 04: How do I build or acquire a decoder interface circuit? If you want to decode trunk control, MDT, pager, fax or other digital signals, you will need to build or buy a simple Interface to go between the NFM Discriminator/baseband audio of the scanner and a standard serial port on the PC. If you are not capable of building your own, or if you don't have the time to mess with it, I can supply an assembled/tested Decoder Interface, built inside a DB-25 shell and connector with a 2-to-3 ft shielded cable terminated with an RCA plug, for US$35 plus $5 S&H domestic. See my signature box at the end of this article. The DB-25 shell connects directly to a DB-25 comport on the PC, or, if your comports are DB-9's, you can get a DB25-to-DB9 adapter for it. You should, however, be able to make your own following the below instructions. This is a tried and true Data Interface circuit that is good for everything we've tried, including a wide variety of scanners. External power is not required. This circuit draws its power from the comport. It is similar to the "Hamcomm" and "data slicer" interfaces, but is optimized for more scanners and more applications. SCANNER DATA DECODER INTERFACE SCHEMATIC DIAGRAM Copyright (c) 1998 Bill Cheek Computer Serial Port Scanner |<------circuit----------------->| DB25 DB9 ==== === o----o--|<--------o---->20 DTR 4 1.0 to | | 1N4148 | NFM 4.7-uF |\ | o--|<--------|-o--> 4 RTS 7 >------]|+-----o----|2 \ | | | | DSCR | | \ o--+|[-->>> | | 100k | |LM 7 \ 10-uF | | >--o--/\/\/----o |741 6 >----------o---|-|--> 5 CTS 8 GND | | / | | | o--/\/\/--o------|3 4/ | | | | 3.3k | | / | | | | | See | |/ | | | | | Note 8 o-----------|----/\/\/----o | | | | 100k | | | | | | o---------------------|-----------------|-|--> 7 Gnd 5 | | | | | o-------->|-------o | | 10-uF | 1N4148 | o-------------+|[-----o-------->|---------o | o--->>>Ground LEGEND: o = soldered connection/junction --|-- = crossover (no connection) +|[ = capacitor, polarized (see +) >| = diode (anode->|-cathode) |< = diode (cathode-|<-anode) -/\/\/- = resistor -->>> = ground NOTES: 1. Use tantalum capacitors, +|[ polarity as shown 2. Radio Shack's LM-741 works fine. Others might not! 3. Use 1/4 or 1/8 watt resistors to save space 4. Build circuit on a trimmed and fitted piece of perf board inside a DB-25 shell for max efficiency and space savings. DB-25 connects to PC's comport and a shielded cable from the scanner goes to the input; shield is ground and center is audio. 5. Many handheld scanners have no space to install a phone jack for the NFM Discriminator Output. For such tight spaces a strip of 3 pinline sockets can be melted into the plastic case and wires soldered to the inside protrusions. The middle pinline socket is not connected to anything; it's just there as strength and support for the pinline plug you make, with the shield ground soldered to one end and the audio-center soldered to the other end: GND---o o o---NFM DSCR (audio) 6. For base scanners, install a female RCA jack on rear panel. 7. For handheld scanners where there is space, use a 3/32" mini or a 1/8" standard monaural phone plug. 8. 3.3k is an optimized value for most applications. If the baseband audio output is less than 400-mV AC, you can decrease the 3.3k resistor to 2.2k or even 1k if needed. 9. Connect the interface to a comport on the PC. Plug the input cable in to the scanner's NFM Discriminator Output Jack. Tune to a desired signal and run the decoder software of your choice. ================================================================== 05: So how do I decode digital data from the airwaves? First, you tap the Discriminator Output in your scanner. Then build the Decoder Interface and connect it to the Discriminator Output. Then connect the other side of the Decoder Interface to a com/serial port on your PC. Lastly, run the software that decodes the particular type of signal that you want to decode. In general, it takes different software for different kinds of signals, and I can't possibly cover them all here. I will suggest that you start out with a free program called TRUNKER that decodes the control data of Motorola trunking systems. This is one of the easiest to set up and get working; therefore, it makes a good test "platform" to prove up all your work before you venture into bigger and better things. Motorola trunk systems are fairly common now. TRUNKER and a good set of documentation and limited support for it can be found at the following URLs (Web Sites): http://www.geocities.com/CapeCanaveral/Lab/1060/beta.htm or http://web2.airmail.net/lblant1/dfw/digital.htm ============================================================= 06: How can I decode CTCSS, DPL, and DTMF from the airwaves? That is strictly up to specialized hardware and/or software that kind of goes beyond the scope of this FAQ. Lots of software is out and about that will do it, and there are even possibilities for "roll your own" hardware decoders. But the first thing you'll need is the "baseband audio" output that is described in Questions/Answers #1-3 above. The Data Decoder Interface described in Q/A #4 is good ONLY for trunking and pager types of data; not CTCSS, DPL, and DTMF, unfortunately. In fact, it takes specialized hardware and/or software to decode each of CTCSS, DPL, and DTMF; and each is as different as night and day. Some scanners come equipped for CTCSS decoding, but most do not. And none come equipped for DPL or DTMF that I know of. For more information about retrofitting CTCSS and DPL decoders to your scanner, contact: Communications Specialists, Inc. 426 West Taft Avenue Orange, CA 92865-4296 (800) 854-0547 Fax (800) 850-0547 (714) 998-3021 Fax (714) 974-3420 WEB: http://www.com-spec.com/ For a low-cost "roll-your-own" DTMF Decoder (hardware) there is a nice project done up in great detail in one of the back issues of the monthly WORLD SCANNER REPORT newsletter, V3N10. Backissues are always available at a nominal cost. See: ftp://ftp.cts.com/pub/bcheek Download PRODINFO.ZIP There are other hardware and software solutions for decoding DTMF that I may include here later as I get the information verified and added. The WiNRADiO Digital Suite is awesomely capable of decoding CTCSS and DTMF. See: http://www.winradio.com For scanners in general, though, it all starts with a tap to the "baseband audio" point, so read over Q&A 1-3 above for the details. ============================================================= 07: Is it possible to "TrunkTrack" without a TrunkTracker? It didn't used to be, but times do change and YES! It is now possible to track the trunks without a 'real' TrunkTracker Scanner, and better, for that matter!!! Like the other subjects in this FAQ, it all begins with a Data Decoder Interface. Next, you need a PRO-2004, PRO-2005, or PRO-2006 scanner, although we hope to add other scanners to the list in due time. For now, it's one of those three. Then you need a CE-232 Scanner/Computer Interface (or its predecessor, the HB-232). You will also need the hot, new Windows program for the CE/HB-232 called Pro-Turbo. Lastly, you need one fairly modern computer, Pentium 133 or better, for the easiest way to track the trunks, but there is another way almost as easy, if you have two computers, one a 486DX2/66 or better and the other, a PC-386 or better. There are other requirements, too, but the above are the main ones. It is beyond the scope of this FAQ to spell out all the details, but the V8N9 issue of the monthly World Scanner Report tells it all. You can order this or any other back issue of the World Scanner Report since Jan-91, including 6-mo and 1-yr subscriptions directly from me. For more information on the Pro-Turbo software for the HB/CE-232, contact: Paul E. Turton RR # 3 Wainfleet, Ontario Canada L0S 1V0 E-mail: pturton@iaw.on.ca or jabba@iaw.on.ca Web: http://www.iaw.on.ca/~jabba/pro-turbo.htm For more information on the CE-232 Interface, you can download a file called PRODINFO.ZIP from: ftp://ftp.cts.com/pub/bcheek or ask for it as an e-mail file attachment from: bcheek@cts.com or see the information in my signature box below. But yes, it is now possible to track the trunks without a TrunkTracker scanner, and do it better than any of the "real" TrunkTracker scanners! The cost can be a lot less than the cost of a real TrunkTracker, too. The cost largely depends on what you already have, but if you don't have a CE-232 and Pro-Turbo, then you're looking at an outlay of roughly $150 or so to get started. Incidentals and bit parts could add another $50, assuming you have at least a PRO-2004, PRO-2005, or PRO-2006. Contact me for the latest on this exciting topic. ============================================================= That's it for now. I will keep this FAQ updated. If you see things that need to be added to it, by all means, let me know. If this FAQ fails to address your question(s), then hit me with 'em again, but be specific. And be detailed with symptoms and observations if you need tech support on mods or troubleshooting and diagnosis. Use e-mail if you can. Copyrighted (c) 1998 (All rights reserved) Revised 11/03/98 ------------------------------------------------- --- Bill Cheek - President/CEO/Publisher \ / COMMtronics Engineering/World Scanner Report \ / Box 262478 ~ San Diego ~ CA ~ 92196-2478 \/ E-mail: bcheek@cts.com /\ ftp://ftp.cts.com/pub/bcheek / \ http://ourworld.compuserve.com/homepages/bcheek / \ ------------------------------------------------- --- ========================END OF FILE===========================