An article for building a tunable notch filter to block data streams sent just above the FM band was in the April 1992 issue of Radio-Electronics (pp. 37-39). Notch filters (as well as kits for them) for other frequencies are frequently advertised in Nuts & Volts magazines as beep filters and the like.
Becoming more and more popular, not only because of the Cable Act of 1992 but also in an effort to stop pirates are addressable taps. Many cable companies will be moving to this technology in the near future, (which they call interdiction). These are devices located at the pole, where your individual cable feed is tapped from the head-end. Similar to addressable converters, they each have a unique ID number and can be turned on/off by a computer at the head-end. Any stations which you are not paying for are filtered out by electronicly switchable traps in the units. (Including the whole signal if you haven't paid your bill or had the service disconnected.) {Several patents have already been issued for various methods of making SURE you don't see a channel you don't pay for.} Again, these almost guarantee an end to piracy and don't have any of the disadvantages of the manual traps. Plus, they provide a superior signal to those customers paying for service because they no longer need complicated cable boxes or A/B switches -- and they can finally use all of the cable-ready capabilites of the VCR, TV, etc. About the only known attack on this type of system is to splice into a neighbors cable, which again provides plenty of physical evidence for prosecution.
The horizontal sync pulses of an SSAVI signal can be absent completely, at the wrong level, or even present, and can be varied on a field-by-field basis. Any decoder for an SSAVI (or similar) system has to be able to separate a video line into its two basic components-- the control and picture signals. In SSAVI, the horizontal sync is never inverted, even if the picture is. So a method of inverting the picture without inverting the control section is necesary. This is complicated by the fact that almost every line in an SSAVI signal has no horizontal sync information, making it difficult to perform the separation (since the usual reference point--the horizontal sync pulse--is gone).
In the older suppressed-sync system, the sync pulse could be recovered from the gating signal buried in the audio subcarrier, but SSAVI is pilotless. The key to this system relies on the strict timings imposed by the NTSC standard--if you can locate one part of the signal accurately, you can determine where everything else should be mathematically. Since the cable company is sending a digital data stream---the security and access-rights--during the VBI of the signal, the VBI makes a great place to find a known point in the signal. Obviously if the electronics in the cable box can locate this information, so can electronics outside the cable box! :-)
The only constant in the SSAVI system are the horizontal sync pulses during the VBI (the first 26 lines of video), which are sent "in the clear". The pulses from the VBI can be used as a reference for a phase-locked loop (PLL) and used to supply the missing pulses for the rest of the video frame. With 20 or so reliable pulses at the beginning of each frame, you can accurately generate the missing 240 or so pulses. Of the 26 lines in the VBI, lines zero through nine are left alone by request of the FCC, lines 10 to 13 are commonly used to transmit a digital data stream, line 21 contains closed-caption information, while other lines are used for a variety of stuff depending on the cable system and the channel you're watching. When you tune to a scrambled channel with a cable box, logic circuits in the unit count the video lines, read the transmitted data stream, and compare the transmitted data with the information stored in the box. If the box is authorized to receive the signal with that particular data stream, the decoder is enabled and the scrambled signal becomes viewable. If not, the signal is passed through without being decoded, or more commonly, a barker channel (whose channel number is sent via the data stream) is automatically tuned instead. This prevents people from using the unit as a tuner for add-on descramblers often advertised in the back of electronics magazines.
In the SSAVI system, the video can be sent with either normal or inverted picture information. The descrambler needs a way to determine whether to invert the video or not. Originally this information could be found on line 20, but has since moved around a lot as the popularity (and knowledge) of the system increased. In any event, the last half of the line would tell the decoder whether to invert the picture or not. If the rest of the field was not inverted, the last half of the line would be black. If the video in the rest of the frame was inverted, the last half of the line would be white.
The Drawing Board column of Radio-Electronics starting in August '92 and going through May '93 described the system and provided several circuits for use on an SSAVI system. Note that audio in the system can be scrambled - usually by burying it on a subcarrier that's related mathematically to the IF component of the signal.
Addressable data for Zentih systems is sent in the VBI, lines 10-13, with 26 bits of data per line.
Note that Pioneer boxes are booby-trapped and opening the unit will release a spring-mechanism which positively indicates access was gained to the interior (and sends a signal to the head-end on a two-way system, and may disable the box completely.) {See U.S. patent #4,149,158 for details.} The unit cannot be reset without a special device.
Pioneer systems transmit their addressing data on 110.0 MHz, and there are several programmable cubes that can activate these systems.
The data is a manchester I encoded FSK signal at ~6kHz data rate, this data is easly readable using software developed by Group 42 that will be available on the next release of this disc.
Scientific-Atlanta systems transmit their FSK addressing data on 106.2 or 108.2 MHz. There are several programmable cubes that can activate these systems. On the newest 8600 systems the the addression data is hidden elsewhere, possibly the video blanking region.
The most popular way to defeat these systems is to use a test chip or a cube device to activate the original Jerrold equiptment. Addon descramblers are more difficult to build since you have to convert the signal to baseband levels, descramble, then remodulate the singnal.
Cable Companies have been experementing with several new methods of defeating test chips and cubes, most notably is the use of Multi Mode and adding an extra checksum byte in the FSK data packet format. Pirates are starting to clone cable companies test boxes to get around the most problem areas of multi mode and newer test chips and cubes are getting smarter to combat both multimode and the extra checksum bytes.
A two-piece unit (combo) usually consists of an any-brand cable TV tuner with a third-party descrambler (often referred to as a pan) which is designed to work with a specific scrambling technology. The descrambler typically connects to the channel 3 output of the tuner, and has a channel 3 output which connects to your TV. (Although some tuners have a decoder loop for such devices.) They have the advantage that if you move or your system is upgraded, you can try to purchase a new descrambler -- which is much cheaper than a whole new set-up. You also can select the cable TV tuner with the features you want (remote, volume control, parental lockout, baseband video output, etc.) Two-piece units typically cannot be disabled by the data stream on your cable. (Note however that there ARE add-on pans manufactured by the same companies who make the one-piece units that DO pay attention to the data stream and can be disabled similarly!) The main disadvantage is that a third-party descrambler MAY not provide as high of quality descrambling as the real thing, and it may arrouse suspicion if someone notices your cable thing is different from theirs.
__ __ __ __ - __ __ __ | | | | | | | | | | | | | |___ T = two-way capability, C = PROM programmable | | | | | | | | | | | |______ DI = Inband decoder, DO = Outband decoder, | | | | | PC = Single pay channel, A = Addressable | | | | | | | | | |_________ Output channel number (3 very common) | | | | | | | |______________ D or I = tri-mode system, N = parental lockout | | | feature (6 dB-only systems are "blank" here) | | | | | |_________________ M = mid-band only, X = thru 400 MHz, | | Z = thru 450 MHz, BB = baseband | | | |____________________ S = Set-top, R = Remote | |_______________________ D = Digital tuning, J = Analog tuningAlso note that some Jerrold converters (particularly the DP5 series and some CFTs) have a tamper-switch, and that opening the box will clear the contents of a RAM chip in the converter. This may or may not be corrected by letting the unit get refreshed by the head-end FSK data stream.
Most Jerrold systems in the United States and Canada transmit their addressing data on 97.5, 106.5 or 108.5 MHz. Some DPV7 and DPBB7 models have S7, S8, or S9 as the last numbers on there modle numbers, these correlate to 97.5, 106.5 and 108.5 Mhz directly. CFT model numbers almost always use 108.5Mhz. DPV5 and older units mostly use 106.5Mhz. In Europe 122.75 Mhz seems to be the addressing frequency used, at least in several parts of Jolly old England.
The datastream is Manchester II encoded FSK, with approximately a 14kHz clock. And is fully readable with software developed by Group 42 available on a future relase of this disc.
Model 8600 - _ _ _ _
| | | |
| | | |___ Impulse PPV Return: N=none, T=telephone, R=RF
| | |_____ Dual cable option: N=none, D=dual cable
| |_______ Descrambler type: S=SA standard, K=oak
|_________ Channel: S=selectable channel 3/4
The 8600 has 240 character on-screen display, multimode scrambling,
8 event 14 day timer, and is "expandable"...
Model 859_ - 7 _ 7 _
| | |
| | |__ Dual cable option: D=dual cable
| |______ Descrambler: 5=SA scrambling+video inversion,
| 7=5+Oak
|____________ 0=No Impulse PPV, 5=Telephone IPPV, 7=RF IPPV
The 8590s feature volume control, multimode scrambling, 8 event
14 day timer...
Model 858_ - _ 3 _ - _
| | | |__ Dual cable option: D=dual cable
| | |______ Data carrier: 6=106.2 MHz, 8=108.2 MHz
| |__________ Channel: 3=channel 3, 4=channel 4
|______________ 0=No Impulse PPV, 5=Telephone IPPV, 7=RF IPPV
The 8580s use dynamic sync suppression, 8 event 14 day timer, and
built-in pre-amp.
The 8570 is similar to the 8580.
Model 8550 - _ _ _
| | |__ 1=108.2 MHz data stream
| |____ Jerrold, dropfield, SA descrambling
|______ Channel: 3=channel 3
The 8550 is not a current model; it can be replaced with an 8580-321.
Non-addressable products include the 8511, 8536, 8540 and 8490.
The SA models below 8600 transmit there FSK addressing data on one of two frequencies. It is ~32kHz Manchester I encoded signal that is easly read by software developed by Group 42 avalable on the next release of this disc.
This new data signal tells whatever boxes the cube addresses to go into full-service mode (including any cable company-provided boxes). Sometimes it is a non-destructive signal, and if the the cube is removed from the line, the real data signal gets to the electronics inside and the converter goes back to normal non-test mode. Note that sometimes it IS destructive: there are some cubes that re-program the electronic serial number in a converter to a new value. This type has the advantage that it will work with any converter the cube was designed to test (but changes the serial number to some preset value). The non-destructive versions of a cube usually require that you provide the serial number from the converter you're interested in testing. That way a custom IC can be programmed to address that converter with the necessary data. (Otherwise the converter would ignore the information, since the serial number the cube was sending and the one in converter wouldn't match.)
The best cubes that we have seen are the Stealth FSK and RFT-2 units. These seem to offer the most trouble free performance, don't require a serial number, and are non-destructive devices.
There are some newer cubes on the market called genesis FSKs that will reboot (or reactivate) a shut down box.
The bullet is NOT a harmful high-voltage signal or something as the cable companies would like you to believe -- if it was, it would damage anyone with a cable-ready TV or VCR connected to the cable (not something the cable company wants to deal with!)
The only way to get caught by such a signal is to contact the cable company and tell them your illegal descrambler just quit working for some reason. :-) Not a smart thing to do, but you'd be surprised, especially if it's someone else in the house who calls, like a spouse, child, babysitter, etc. While we're on the subject, it's also not a good idea to have cable service personnel come into your residence and find an unauthorized decoder...
The cable company also has various ways of detecting signal leaks in their cable. The FCC REQUIRES them to allow only so much signal to be radiated from their cables. You may see a suspicious looking van driving around your neighborhood with odd-looking antennas on the roof. These are connected inside to field strength meters which help locate where the leaks are coming from so they can be fixed (to prevent a fine from the FCC!) If you've tampered with a connection at the pole (say, to hook up a cable that had been disconnected) and didn't do a good job, chances are the connection will "leak" and be easily found by such a device. This can also happen INSIDE your residence if you use cheap splitters/amplifiers or have poorly-shielded connections. The cable company will ask to come inside, and bring with them a portable field strength meter to help them locate the problem. Often they will totally remove anything causing the leak, and may go further (e.g., legal action) if they feel you're in violation of your contract with them (which you agree to by paying your bill.) Obviously it's a bad idea to let cable service personnel into your house if you ARE doing something you shouldn't (which you shouldn't be in the first place), but if you DON'T let them in (as is your right), it will definitely arouse suspicion. Eventually you will have to let them in to fix the "leak", or they will disconnect your cable to stop the leak altogether. (After all, it's a service, not a right, to receive cable!)
Of course, the best thing to do is simply PAY FOR WHAT YOU WATCH! Then you don't have to worry about the possibility of a prison term, criminal record, hefty fine, etc.
Since a large number of scrambling systems depend on messing with the horizontal sync pulse to scramble the picture, the Universal Descrambler attempts to use the colorburst signal to help it replace the tainted sync pulse. Unfortunately, random video inversion is still a problem, as are color shifts which occur from distorted or clamped colorburst signals, etc. Most people have not had very good results from the system, even after incorporating some modifications.
Converter: A device, sometimes issued by the cable company, to "convert" many TV channels to one specific channel (usually channel 3). Used early-on when VHF & UHF channels were on different dials (and before remote controls) to provide "convenience" to cable customers. Now mostly considered a nuisance, thanks to the advent of cable-ready video equipment, they are mainly used as descramblers.
An "addresable" converter is one that has a unique serial number and can be told (individually by FSK or other signal) by the head-end to act in a certain manner (such as enabling channel x, but not channel y). Addressable converters nearly always contain descramblers for decoding premium services subscribed to by the customer.
Colorburst: Approximately 8 to 10 cycles of a 3.579545 MHz clock sent during the HBI. This signal is used as a reference to determine both hue and saturation of the colors. A separate colorburst signal is sent for each line of video, and are all exactly in phase (to prevent color shifts).
Control Signal: The first 11.1 microseconds of a line of NTSC video. The signal area from 0 to 0.3 volts (-40 to 0 IRE units) is reserved for control signals, the rest for picture information. If the signal is at 0.3 volts (or 0 IRE) the picture will be black. See IRE Units; Set-up Level.
Cube: A test device that generates an FSK signal to the cable box to activate itself into full service mode also called FSK device or FSK unit. The first Cubes were named because of the cube shaped box that they were sold in.
Field: One half of a full video frame. The first field contains the odd numbered lines, the second field contains the even numbered lines. Each field takes 1/60th of a second to transmit. Note that both fields contain a complete vertical-blanking interval and they both (should) have the same information during that interval. Since the NTSC standard is 525 lines, each field contains 262.5 lines--therefore it's the half-line that allows the two fields of a frame to be distinguished from one another. See Frame; Line.
Frame: An NTSC video signal which contains both fields. A frame lasts 1/30th of a second. See Field; Line.
FSK: Acronym for Frequency Shif Keying. A common data modulation method. Addressable cable systems usually send there control information using this method.
FSK Device: See Cube.
Head-end: The main cable distribution facility where your CATV signal originates from. (Easily identifed by several large satellite dishes, some smaller ones, and usually an antenna tower.)
HBI: Acronym for Horizontal Blanking Interval. The first 11.1 microseconds of a line of video. It contains the front porch, the 4.71 microsecond horizontal sync pulse, the 2.31 microseconds of colorburst, and the back porch. The horizontal sync pulse directs the beam back to left side of the screen. Almost every scrambling method in use today mutataes this part of the signal in some way to prevent unauthorized viewing. See Colorburst.
Interlace: Term used to describe the dual-field approach used in the NTSC standard. By drawing every other line, screen flicker is increased--but if all the lines were painted sequentially, the top would begin to fade before the screen was completely "painted". (Computer monitors, which do "paint" from top to bottom, do not have the problem due to higher refresh rates.)
IPPV: Impulse Pay-Per-View. A method whereby a viewer can order a pay-per-view event "on impulse" by just pushing an "Order" (or similar) button on a remote control or cable converter keypad. A customer's purchases are sent back to the head-end via a standard telephone connection (the converter dials into the cable co. computer and uploads the data) or via radio frequency (RF) if the cable supports two-way communication (most don't). A pre-set maximum number of events can be ordered before the box requires the data to be sent to the head-end for billing purposes.
IRE Units: IRE is an acronym for Institute of Radio Engineers. The NTSC standard calls for a peak-to-peak signal voltage of 1 volt. Instead of referring to the video level in volts, IRE units are used instead. The IRE scale divides the 1- volt range into 140 parts, with zero-IRE corresponding to about 0.3V. The full scale goes from -40 IRE to +100 IRE. This is convenient scale to make a distinction between control signals (< 0 IRE) and picture signals (> 0 IRE). See Control Signal.
Line: A video signal is a series of repeated horizontal lines, consisting of control and picture information. The color NTSC standard allows a total time of 63.56 microseconds for each line, and each frame is composed of 525 lines of video information. The first 11.1 microseconds make up the horizontal blanking interval, or control signal, the following 52.46 microseconds make up the picture signal. See HBI; VBI.
NTSC: Acronym for National Television Standards Committee (or Never The Same Color, if you prefer :-)
Picture Signal: The 52.46 microseconds of signal following the control signal. Information in this area is between 0 and 100 IRE units. See IRE Units.
PPV: Acronym for Pay-Per-View. A revenue-enhancing system where customer's pay to watch a movie or event on a "per view" basis. Cusomers usually place a phone call to a special number and order the event of their choice; some systems provide Impulse PPV. The presence of a PPV movie channel or your system guarantees you have addressable converters. See IPPV.
Set-up Level: Picture information technically has slightly less than 100 IRE units available. That's because picture information starts at 7.5 IRE units rather than at 0 IRE units. The area from 0 to 7.5 IRE units are reserved for what is commonly called the "set-up level". Having a small buffer area between the control signal information and the picture information is a "fudge factor" to compensate for the fact that real-life things that don't always work as nicely as they do on paper. :-) See IRE Units.
VBI: Acronym for Vertical-Blanking Interval. The first 26 lines of an NTSC video signal. This signal is used to direct the beam back to the upper-left corner of the screen to start the next frame. In order for the horizontal sync to continue operating, the vertical pulse is serrated into small segments which keep the horizontal circuits active. Both actions can then take place simultaneously. The VBI is the most common place for "extra" information to be sent, such as various test signals, and in some cable systems, a data stream.
Some older TV sets can't receive any channels except 5 and 6 on an HRC system, and can't receive channels 5 and 6 on an IRC system. This is also true of some cable converters. A few converters are set up to allow HRC or IRC operation but with channels 5 and 6 on different numbers -- 55 and 56, or 55 and 66. (Tnx to David Sharpe and Ed Ellers for this info!)
Center Video Color Sound Osc.
Channel Band Freq. Carrier Carrier Carrier Freq.
TVIF 40-46 43 41.25 44.83 47.75 ---
2 54-60 57 55.25 58.83 59.75 101
3 60-66 63 61.25 64.83 65.75 107
4 66-72 69 67.25 70.83 71.75 113
5 76-82 79 77.25 80.83 81.75 123
6 82-88 85 83.25 86.83 87.75 129
FM-1 88-94 91 89.25 92.83 93.75 --- FM-2 94-100 97 95.25 98.83 99.75 --- FM-3 100-106 103 101.25 104.83 105.75 ---
A2-(00) 108-114 111 109.25 112.83 113.75 155 A1-(01) 114-120 117 115.25 118.83 119.75 161 A-(14) 120-126 123 121.25 124.83 125.75 167 B-(15) 126-132 129 127.25 130.83 131.75 173 C-(16) 132-138 135 133.25 136.83 137.75 179 D-(17) 138-144 141 139.25 142.83 143.75 185 E-(18) 144-150 147 145.25 148.83 149.75 191 F-(19) 150-156 153 151.25 154.83 155.75 197 G-(20) 156-162 159 157.25 160.83 161.75 203 H-(21) 162-168 165 163.25 166.83 167.75 209 I-(22) 168-174 171 169.25 172.83 173.75 215
7 174-180 177 175.25 178.83 179.75 221
8 180-186 183 181.25 184.83 185.75 227
9 186-192 189 187.25 190.83 191.75 233
10 192-198 195 193.25 196.83 197.75 239
11 198-204 201 199.25 202.83 203.75 245
12 204-210 207 205.25 208.83 209.75 251
13 210-216 213 211.25 214.83 215.75 257
J-(23) 216-222 219 217.25 220.83 221.75 263 K-(24) 222-228 225 223.25 226.83 227.75 269 L-(25) 228-234 231 229.25 232.83 233.75 275 M-(26) 234-240 237 235.25 238.83 239.75 281 N-(27) 240-246 243 241.25 244.83 245.75 287 O-(28) 246-252 249 247.25 250.83 251.75 293 P-(29) 252-258 255 253.25 256.83 257.75 299 Q-(30) 258-264 261 259.25 262.83 263.75 305 R-(31) 264-270 267 265.25 268.83 269.75 311 S-(32) 270-276 273 271.25 274.83 275.75 317 T-(33) 276-282 279 277.25 280.83 281.75 323 U-(34) 282-288 285 283.25 286.83 287.75 329 V-(35) 288-294 291 289.25 292.83 293.75 335 W-(36) 294-300 297 295.25 298.83 299.75 341
AA-(37) 300-306 303 301.25 304.83 305.75 347 BB-(38) 306-312 309 307.25 310.83 311.75 353 CC-(39) 312-318 315 313.25 316.83 317.75 359 DD-(40) 318-324 321 319.25 322.83 323.75 365 EE-(41) 324-330 327 325.25 328.83 329.75 371 FF-(42) 330-336 333 331.25 334.83 335.75 377 GG-(43) 336-342 339 337.25 340.83 341.75 383 HH-(44) 342-348 345 343.25 346.83 347.75 389 II-(45) 348-354 351 349.25 352.83 353.75 395 JJ-(46) 354-360 357 355.25 358.83 359.75 401 KK-(47) 360-366 363 361.25 364.83 365.75 407 LL-(48) 366-372 369 367.25 370.83 371.75 413 MM-(49) 372-378 375 373.25 376.83 377.75 419 NN-(50) 378-384 381 379.25 382.83 383.75 425 OO-(51) 384-390 387 385.25 388.83 389.75 431 PP-(52) 390-396 393 391.25 394.83 395.75 437 QQ-(53) 396-402 399 397.25 400.83 401.75 443 RR-(54) 402-408 405 403.25 406.83 407.75 449
14 470-476 473 471.25 474.83 475.75 517 15 476-482 479 477.25 480.83 481.75 523 16 482-488 485 483.25 486.83 487.75 529 17 488-494 491 489.25 492.83 493.75 535 18 494-500 497 495.25 498.83 499.75 541 19 500-506 503 501.25 504.83 505.75 547 20 506-512 509 507.25 510.83 511.75 553 21 512-518 515 513.25 516.83 517.75 559 22 518-524 521 519.25 522.83 523.75 565 23 524-530 527 525.25 528.83 529.75 571 24 530-536 533 531.25 534.83 535.75 577 25 536-542 539 537.25 540.83 541.75 583 26 542-548 545 543.25 546.83 547.75 589 27 548-554 551 549.25 552.83 553.75 595 28 554-560 557 555.25 558.83 559.75 601 29 560-566 563 561.25 564.83 565.75 607 30 566-572 569 567.25 570.83 571.75 613 31 572-578 575 573.25 576.83 577.75 619 32 578-584 581 579.25 582.83 583.75 625 33 584-590 587 585.25 588.83 589.75 631 34 590-596 593 591.25 594.83 595.75 637 35 596-602 599 597.25 600.83 601.75 643 36 602-608 605 603.25 606.83 607.75 649 37 608-614 611 609.25 612.83 613.75 655 38 614-620 617 615.25 618.83 619.75 661 39 620-626 623 621.25 624.83 625.75 667 40 626-632 629 627.25 630.83 631.75 673 41 632-638 635 633.25 636.83 637.75 679 42 638-644 641 639.25 642.83 643.75 685 43 644-650 647 645.25 648.83 649.75 691 44 650-656 653 651.25 654.83 655.75 697 45 656-662 659 657.25 660.83 661.75 703 46 662-668 665 663.25 666.83 667.75 709 47 668-674 671 669.25 672.83 673.75 715 48 674-680 677 675.25 678.83 679.75 721 49 680-686 683 681.25 684.83 685.75 727 50 686-692 689 687.25 690.83 691.75 733 51 692-698 695 693.25 696.83 697.75 739 52 698-704 701 699.25 702.83 703.75 745 53 704-710 707 705.25 708.83 709.75 751 54 710-716 713 711.25 714.83 715.75 757 55 716-722 719 717.25 720.83 721.75 763 56 722-728 725 723.25 726.83 727.75 769 57 728-734 731 729.25 732.83 733.75 775 58 734-740 737 735.25 738.83 739.75 781 59 740-746 743 741.25 744.83 745.75 787 60 746-752 749 747.25 750.83 751.75 793 61 752-758 755 753.25 756.83 757.75 799 62 758-764 761 759.25 762.83 763.75 805 63 764-770 767 765.25 768.83 769.75 811 64 770-776 773 771.25 774.83 775.75 817 65 776-782 779 777.25 780.83 781.75 823 66 782-788 785 783.25 786.83 787.75 829 67 788-794 791 789.25 792.83 793.75 835 68 794-800 797 795.25 798.83 799.75 841 69 800-806 803 801.25 804.83 805.75 847 70* 806-812 809 807.25 810.83 811.75 853 71* 812-818 815 813.25 816.83 817.75 859 72* 818-824 821 819.25 822.83 823.75 865 73* 824-830 827 825.25 828.83 829.75 871 74* 830-836 833 831.25 834.83 835.75 877 75* 836-842 839 837.25 840.83 841.75 883 76* 842-848 845 843.25 846.83 847.75 889 77* 848-854 851 849.25 852.83 853.75 895 78* 854-860 857 855.25 858.83 859.75 901 79* 860-866 863 861.25 864.83 865.75 907 80* 866-872 869 867.25 870.83 871.75 913 81* 872-878 875 873.25 876.83 877.75 919 82* 878-884 881 879.25 882.83 883.75 925 83* 884-890 887 885.25 888.83 889.75 931