The LOD/H Technical Journal: File #8 of 12 *** NOTE *** BECAUSE OF THE LENGTH OF THIS GUIDE, IT HAS BEEN BROKEN INTO TWO PARTS FOR TRANSMISSION. HOWEVER, IT IS ONE VOLUME, AND IS INTENDED TO BE PRINTED AS A WHOLE FOR USE AS BOTH A TUTORIAL AND A REFERENCE GUIDE. ********************************* The Legion of Doom! Presents: ------------- LOD Reference Guide Vol. I Outside Loop Distribution Plant -------------- Written 12/86 Phucked Revision III Agent 04 ********************************* ---------------------- INTRODUCTION / OUTLINE ---------------------- Basically, the outside local loop distribution plant consists of all of the facilities necessary to distribute telephone service from the central office (CO) out to the subscribers. These facilities include all wire, cable, and terminal points along the distribution path. In this article, we shall follow this path from the CO to the subscriber, examining in depth each major point along the route and how it is used. This is especially useful for checking if any 'unauthorized equipment' is attached to your line, which would not be attached at the Central Office. I suppose this article can also be interpreted to allow someone to do just the opposite of its intended purpose... Note that this article is intended as a reference guide for use by persons familiar with the basics of either LMOS/MLT or the operation of the ARSB/CRAS (or hopefully both), because several references will be made to information pertaining to the above systems/bureaus. I have no manuals on this topic, all information has been obtained through practical experience and social engineering. ******************** -------------------------------- Serving Area Concepts (SAC) plan -------------------------------- In order to standardize the way loop distribution plants are set up in the Bell System of the U.S. (and to prevent chaos), a reference standard design was created. For urban and suburban areas, this plan was called the Serving Area Concepts (SAC) plan. Basically, in the SAC plan, each city is divided into one or more Wire Centers (WC) which are each handled by a local central office switch. A typical WC will handle 41,000 subscriber lines. Each WC is divided into about 10 or so Serving Areas (depending on the size and population of the city), with an average size of 12 square miles each (compare this to the RAND (Rural Area Network Design) plan where often a rural Serving Area may cover 130 square miles with only a fraction of the number of lines). Each Serving Area may handle around 500-1000 lines or more for maybe 200-400 hous- ing units (typically a tract of homes). From the CO, a feeder group goes out to each Serving Area. This con- sists of cable(s) which contain the wire pairs for each line in the SA, and it is almost always underground (unless it is physically impossible). These feeder cables surface at a point called the Serving Area Interface (SAI) in a pedestal cabinet (or "box"). From the SAI, the pairs (or individual phone lines) are crossed over into one or several distribution cables which handle different sections of the SA (ie. certain streets). These distribution cables are either of the aerial or underground type. The modern trend is to use buried distribution cables all the way to the subscriber premises, but there are still a very large number of existing loop plants using aerial distribu- tion cables (which we will concentrate mainly upon in this article). These distribution cables are then split up into residence aerial drop wires (one per phone line) at a pole closure (in aerial plant), or at a cable pair to service wire cross box (in buried plant). The cable pairs then end up at the station protector at the customer's premises, where they are spliced into the premise "inside wire" (IW) which services each phone in the customer's premi- ses (and is also the customer's responsibility). Although this is the "standard" design, it is by no means the only one! Every telco makes it's own modifications to this standard, depending on the geographic area or age of the network, so it's good to keep your eyes and your mind open. ******************** At this point, we will detail each point along the Loop Distribution Plant. ----------------------------- Cable Facility F1 - CO Feeder ----------------------------- The F1 cable is the feeder cable which originates at the Main Distribu- tion Frame (MDF) and cable vault at the local CO and terminates at the SAI. This cable can contain from 600 to over 2000 pairs, and often more than one physical F1 cable is needed to service a single Serving Area (at an SAI). The F1 is almost always located underground, because the size, weight, and number of feeders leaving the CO makes it impossible to put them on normal telephone poles. Since is is also impractical to use one single piece of cable, the F1 usually consists of several pieces of large, pressurized or armored cable spliced together underground (this will be covered later) into a single cable. Cable Numbering --------------- In order to make locating cables and pairs easier (or possible, for that matter), all of the cables in the loop distribution plant are numbered, and these numbers are stored in databases such as LMOS at the ARSB or other records at the LAC (Loop Assignment Center) or maintenance center. When trying to locate someone's cable pair, it helps a great deal to know these numbers (although it can be done without them with experience and careful observa- tion). Probably the most common place to find these numbers is on a BOR, in the "Cable & Assignment Data" block. The F1 is usually assigned a number from 00 to 99 (although 000-999 is sometimes used in large offices). Cable >pair< numbering is different however, especially in older offices; typical F1 pair numbers range from 0000 to 9999. Keep in mind that the pair number is not concrete -- it is merely nominal, it can change, and it doesn't necessarily have any special meaning (in some well organized offices, however, the cables and pairs may be arranged in a certain way where you can determine what area it serves by its number (such as in my area...heh heh); in any case, it's up to you to figure out your area's layout). Anyway, the cable-pair number is usually written in a format such as 02-1495, where 02 is the cable and 1495 is the pair (incidentally, since this is the CO Feeder cable pair that is connect- ed to the MDF, it is the one that will be listed in COSMOS). F1 Access Points ---------------- Although the F1 is run underground, there is really not a standard access point down there where a certain pair in a cable can be singled out and accessed (as will be explained next). There is, however, a point above ground where all the pairs in the F1 can be accessed -- this point is known as the Serving Area Interface (SAI), and it will be detailed later. In LMOS or other assignment records, the address of the SAI will be listed as the TErminal Address (TEA) for the F1 cable handling a certain pair in question; therefore, it is where facility F1 stops. ----------------- Underground Plant ----------------- The term "Underground Plant" refers to any facilities located below the surface of the earth; this includes truly "buried" cables, which are located 6-or-so feet underground surrounded basically by a conduit and dirt, as well as cables placed in underground cement tunnels along with other "below-ground" equipment (such as seen in most urban areas). Whereas the first type is really impossible to access (unless, of course, you want to dig for a day or so and then hack into an armored, jelly-filled PIC cable-- then you should take a bit of advice from our resident Icky-PIC "Goo" advisor, The Marauder), the latter type can be accessed through manholes which lead to the underground tunnel. Manholes -------- Bell System manholes are usually found along a main street or area where a feeder cable group passes through. Using an underground cable location map is the best method for locating cable paths and manhole appear- ances, although it may not always be available. These maps can be acquired from the Underground Service Alert (USA) (at 800-422-4133), but often a "cable locator" will be dispatched instead (usually he will just mark off how far down or where you can dig without hitting a cable), so this is not a very practical method. Of course, you can always follow the warning signs on telephone poles ("call before you dig", etc) and the spans between SAI bridging heads until you find a manhole. The F1 for the SAI nearest the manhole should be found down there along with others en route to the areas they serve. There are several types of manhole covers, both round and rectangular. The rectangular ones are sometimes just hinged metal plates covering an under- ground terminal or cable closure, and these are easily opened by one person. A non-hinged one may require two people. Round manhole covers (which, by the way, are round so that a lineman can't accidentally drop the cover down the hole) are basically all the same, except for the types known as "C" and "D" type manhole covers which utilize locking bolts (these can be removed using a standard crescent or hex socket wrench). These covers are the same as the order. This is aided even further by the fact that since F1's usually last longer than F2 facilities, there are often more spare provisional F2 facili- ties in the loop plant (ie. 100 feeders in, 300 F2 out (200 aren't cross- connected to F1's)). So there is a good chance that you will find one that is distributed to your area. Other spare facilities include "floaters", which are like spare feeder pairs, except they are ACTIVE lines. Often, a telco will extend whole feeder groups to more than one SAI in provision for future expan- sion, including active cable pairs. If you find a working pair on a feeder panel which is not cross-connected to a distribution pair, that pair is a floater. This is by far the best way to covertly access a certain pair, because most linemen will probably not be aware of the pair's presence (it looks unused on the surface). Beware! If you think you can hook up to someone's floater and get free service, you're probably wrong (so many other people have been wrong, in fact, that Pacific Bell has a special "Form K-33" to report this type of fraud), because the telco is more aware of this than you may think. Obviously any toll call you make will show up on the bill for that line. A do-it-yourself spare pair activation can avoid this problem, if done correctly. ******************** End of First half, attach second half here. The LOD/H Technical Journal: File #9 of 12 *** Second half of The Outside Loop Distribution Plant starts here. *** -------------------------------- Cable Facility F2 - Distribution -------------------------------- The F2 distribution cable is the cable which originates from the F1 feeder in the SAI and distributes individual cable pairs to each subscriber. This cable can be one of two types: aerial or buried. The most common is the aerial distribution cable, although buried cable is the modern trend. In the case of aerial F2, the cable or cables leave the SAI underground, and at the first telephone pole on the distribution span, the cable is routed up the pole. It then is suspended on the span, such as down a street, and at each group of houses there is a terminal on the span. This terminal is the aerial drop split- ter, and it's purpose is to break off several pairs from the distribution cable in order to distribute them (in the form of aerial drop wires) to each house or premise. The location or address of the premise nearest this aerial drop splitter is the TErminal Address of the F2 serving a certain pair (each group of pairs in the F2 will have it's own terminal address, unlike the one address for the F1 terminal (SAI)). The F2 cable is always the lowest cable on the telephone pole, and it is usually a great deal larger than the electric power distribution cables above it. Often more than one F2 can be seen on a single pole span. In this case, the top F2 will usually be the one which is being distributed to the subscribers on that street, and the lower (and most often larger) cables are other F2's coming from an SAI and going to the streets which they service: These cables consist of multiple spliced spans, and they will not have any drop wires coming off them (they are marked every few poles or so at a splicing point called a "bullet closure" which is fully enclosed and can be quite large (ie. 6" dia, 20" long) as compared to the normal drop splitters (ie. or similar 4"w x 5"h x 12"l) -- these closures are clamp press- urized and are not meant to be opened unless the cable is being replaced or splicing work is being done. They are not standard cable/pair access points). Buried F2 plant is similar to aerial, except that the cable is not visible because it is underground. Instead of going to a pole from the SAI, the cable continues underground. The drop wires are also underground, and the method of breaking them from the distribution cable is similar to that of the aerial drop splitter, except it is a small pedestal or box located on the ground near the houses it serves. This address closest to this pedestal is the TEA for the F2. F2 Cable Numbering ------------------ The F2 distribution cable is usually given a 4 or 5 digit number, depending on the office. The first 2 or 3 digits should be the number of the F1 that the F2 was branched off of, and the last 2 or 3 digits identify the distribution cable. Example- F1 Cable F2 Cable 25 2531 This F2 cable came from feeder #25^^ The cable >pair< numbers may be set in a similar way, with the last 3 or 4 digits identifying the pair, and the first digit (usually a 1) identifying the pair as a feeder or a distribution pair. Example - F1 Cable Pair F2 Cable Pair 25 1748 2531 748 ^--signifies F1 (feeder) cable pair Generally, the F1 cable pairs are numbered higher than the F2 cable pairs, due to the fact that a feeder cable may contain several distribution cables' worth of cable pairs. Note once again that all of this numbering plan is the STANDARD, and it may be far from real life! As soon as one dist- ribution pair is replaced, crossed over to another feeder pair, or taken from service, the set order is interrupted. In real life, it is most always nece- ssary to get both F1 and F2 cable assignment data. ******************** -------------------------------------------- Facilities F3-F5, Rural Area Interface (RAI) -------------------------------------------- Although cable facilities F3, F4, and F5 may be specified in any loop plant, they are rarely seen anywhere except in rural areas under the RAND plan (Rural Area Network Design). Basically, plants using these extra facilities are similar to F1/F2 plants, except there are extra cable spans and/or terminals in the path. When locating cables, the highest numbered facility will be at the end of the path, terminating near the subscriber's end (like a "normal" F2), and the lowest numbered facility will be the feeder from the CO (like a "normal" F1). The extra spans will be somewhere in between, like an intermediate feeder or extra distribution cable with separate cable access terminals. One such facility is the Rural Area Interface (RAI), which can be used in a "feeder-in, feeder-out" arrangement. This is usually seen on cable routes of 50 pairs or greater, with a length of longer than 30 kft (about 6 miles). In this case, there will be two terminal cabinets in the feeder path, labelled RAI-A and RAI-B. The RAI-A is special because it has a two-part terminal block: the top has switching panels with 108-type connectors which cross-connect feeder-in and feeder-out pairs using jumper plugs, and the bottom has standard 76-type binding posts which cross-connect feeders to distribution cables for subscribers in the local area of the RAI-A. The jumper plugs can only be connected in one way to the switching panels, so random cross-connection of feeder-in/feeder-out pairs is prevented. In this way, the cable and pair numbers stay the same as if the feeder cable was uninterrupted. This is used a lot in rural areas; it allows part of a feeder group to be split off at the RAI-A like a distribution cable near a town along the route, and the rest of the feeder group continues on to a town further away, to the RAI-B where it is terminated as in a "normal" SAI. In order to access a pair, just use the last RAI in the span (whichever it is) and treat it just like an SAI. If the pair terminates at RAI-B, you can also access it at RAI-A! (if you can locate the pair using color code, BP number, or (ughh) ANI, there should be test terminals on top of the jumper plugs connecting the 108's on the switching panel where you can hook your test set -- you can't hook onto a raw 108 connector very easily). Anyway, the RAI terminal is usually a ground pedestal with a cabinet such as a 40-type, but it can be aerial mounted on a pole (hard to access). Pair-Gain, Carried Derived Feeder --------------------------------- Another common facility in rural areas (and in cities or suburbs, es- pecially near large housing complexes, etc.) is the pair-gain system. It is basically a system which consists of a digital link which is distributed, almost like a normal cable pair, out to a terminal cabinet called a Remote Terminal (RT) which contains equipment which demultiplexes the digital line into many "normal" metallic analog telephone lines which go to each subscriber in the area. Because the digital line can transmit the audio from several separate lines and multiplex them onto one cable, only one special cable pair is needed to come from the CO as a feeder, instead of several separate ones; this is why it is called a "pair gain" system. The remote terminal (RT) contains both the demultiplexing electronics as well as a small "SAI" type terminal block for connecting the pairs to distribution cables on the side of the path toward the subscriber. Because the "feeder" is not a multipair cable but a digital link (ie. T-carrier), this arrangement is known as a "carrier-derived feeder." The SAI part of the RT is used just like a normal SAI on the distribution side (BLUE), but the feeder side will be slightly different. Carrier-derived feeders are always marked with YELLOW labels, and their pairs will be crossed over to distribution cables just like in an SAI. So, in order to access a pair in a system like this, you must do so on the DISTRIBUTION side, because you can't hook an analog test set to a 1.544 Mbps digital T-carrier line! (or worse yet, a fiber optic cable). This may be difficult, because these cabinets are always locked (with few exceptions), so you'll have to find a terminal closer to the subscriber -- also be aware that many RT's are equipped with silent intrusion alarms. Anyway, some common pair-gain systems are the Western Electric SLC-8, 40, 96, and GTE's MXU, ranging in size from 8 to over 96 lines. RT cabinets can often be identified by the ventillation grilles (with or without a fan inside) which are not present on SAI's or other non-RT cabinets. ******************** ----------------------------------- Aerial Distribution Splice Closure, Drop Wire Splitter ----------------------------------- This terminal is the point where the individual cable pair for a certain subscriber is split from the F2 distribution cable and spliced onto an aerial drop or "messenger" wire which goes to the subscriber's premises. In an aerial distribution plant, 2 types of this terminal are common: 1> Western Electric 49-type Ready Access Closure / Cable Terminal 2> Western Electric 53A4, N-type Pole Mount Cable Terminals ---------- Type 1> The 49-type, 1A1, 1B1, and 1C1 closures are all functionally similar. This terminal is a semi-rectangular closure, about 15"L x 3"W x 5"H, usually black, which is connected directly to the aerial cable itself; it is coaxial with the cable, so the cable passes straight through it. It splits up to 12 pairs from the distribution cable to a small bin- ding post terminal block inside the closure. Aerial drop wires are then connected to these binding posts, and the wires exit the term- inal through holes on the bottom. These wires are strung via strain relief clamps on the pole down to the subscriber's site. The terminal closure is opened by pulling out and lifting either the whole cover or the front panel after removing the cover fasteners on the bottom and/or the sides (the closure is a thick neoprene cover over an alum- inum frame). Inside the case, there is a terminal block and there may be some sort of loading coil as well. The cable and this coil are not openable, but the terminal block is. Since the F2 pair terminates in this closure, the F2 BP number (cable/assignment data) corresponds to a binding post on this terminal block. As mentioned earlier, this terminal will also contain spare pairs, in case a subscriber wants another line. In order to use one of these pairs, you must either get an F2 (and then F1) CP number from LAC using the BP, or you can put a trace tone on the pair at the aerial closure and then locate the pair at the SAI. Then a cross-connect would have to be made to an active F1 pair, and a drop wire (ughh) would have to be added back at the aerial closure. Anyway, both the binding posts as well as the holes (inside + out) are numbered left to right, so you may not even have to open the closure if you are just looking for an F2 BP number -- just trace the drop wire from the house into the numbered hole on the closure. The TErminal Address for the F2 is the address of the house or premise closest to the pole near this closure. These terminals (esp. 1A1, etc) are also used for straight and branch splices for aerial cables, so you may see one cable in / two out; also, the closure can be used for splicing only, so there may not be drop wires (in this case, it wont be listed in LMOS because it is not a terminal point). There is generally one of these every pole near a quad of houses or so, mounted on the cable about an arm's length from the pole. Type 2> Both the 53A4 and the N-type terminals serve the same function as the 49-type just described, except they are used in situations where there are more than 4 houses (8 lines, including provisional pairs). This terminal is mounted directly on the pole, about a foot down from the aerial cable. It is not connected in line with the cable, so there is no F2 splicing area in the cabinet (rather, a cable stub comes from the terminal block and is spliced onto the span close to where it touches the pole). It is about 22"H x 9"W x 4"D, rectan- gular, and silver (unpainted). The door is similar to that of a 40- type cabinet, but it's much smaller; it is opened using a 7/16" tool in the same manner as before, except that the door must be lifted before it can be opened or closed. In this way, the door slides down on it's hinges when opened, so it locks in the open position and you wont have to worry about it (especially nice because hanging onto a pole is enough of a problem). The terminal block can handle from 25 to 50 pairs, with 32 holes in the back for aerial drop wires. Just as in the Ready Access Closure, this is the F2 terminal, and the numbered binding posts and holes correspond to F2 BP numbers. The TEA will be the address nearest the terminal (just as before). This terminal is common at the first pole on a street, on cul-de-sacs, apartments, marinas & harbors, or anywhere there are many drop wires. Buried Distribution Cross Box and Other Pedestals ------------------------------------------------- This terminal serves the same function as the aerial closures, except it is used in areas with a buried distribution plant. This cable assignment for this terminal will be the F2 terminal, and the BP numbers and TEA will be the same as for the aerial terminals. Probably the most common cross-boxes are the PC4,6, and 12; these are around 50" tall by 4, 6, or 12" square respec- tively, and they are painted gray-green like SAI cabinets. These are the smallest pedestals in the distribution plant, and they don't have doors (they look like waist-high square poles). In order to open one of these pedestals, the two bolts on either side half way down the pedestal must be loosened with a 7/16 hex wrench; then the front cover can be lifted up, out, and off the rest of the closure. These terminals are located generally near small groups of houses (up to about 12 lines usually) on the ground, often near other utility cabinets (such as electric power transformers, etc). These are becoming more common as the new housing tracts use buried distribution plant. The F2 cable will enter as a cable stub, and it is split into service wires which go back underground to the subscribers. All small pedestals are not necessarily the above type of terminal; these pedestal closures are often used for other purposes, such as splicing points in underground distribution, loading coil mounting, and even used as temporary wire storage containers. If the terminal contains a terminal block or it is a significant point on the line, however, it will be listed in LMOS. An example of this is a distribution path found by Mark Tabas in a Mountain Bell area -- there was a small PC12-type closure on the ground near a street in a remote suburb, and it was serving as a terminal point for a whole F1 cable. It was listed as the F1 terminal, and it was at the right TEA; however, there was no terminal block because it was a splicing point (just a bunch of pairs connected with Scotchlok plastic connectors which are hung on a bar in the pedestal closure), so LMOS had no BP number. Instead, a color code was listed (see appendix) for the pair in the splice. Anyway, the WHOLE F1 went up to an N-type closure on a pole and was split into drop wires. -------------------------------------- Multi-Line Building Entrance Terminals -------------------------------------- This terminal takes the aerial drop or service wires and cross-connects them over to the Inside Wire (IW) in the subscriber's building (hotels, busi- nesses, etc). There are many different types of terminal blocks for this terminal, although by far the most common is the Western Electric 66 block. The 66-type terminal uses a block of metal clips; the wire is pushed onto the clip with a punch-down tool which also strips the wire. The block is divided into horizontal rows which can have from 2 to over 6 clips each. Since each row group terminates one pair, two rows are needed for x-connect, one on top of the other. The service or drop wire usually enters on the left, and the inside wire is connected to the far right. In order to locate a pair, usually you can visually trace either the service wire or the inside wire to the block, and often the inside wire side wil be numbered or labelled with an address, phone number, etc. It is also possible for this terminal to serve as an F2 terminal point, if there are a lot of lines. In this case, LMOS will list the TEA usually with some physical direction as to where to find it. The left side will then be numbered as F2 BP's. This terminal is also the demarca- tion point which separates the customer's equipment from the telco's. The new terminals often have an RJ-21 connector on the service wire side, such as a 25-pair for PABX or a Bell 1A2 Key, etc. There are also "maintenance termina- ting units" (MTU) which are electronic units connected to the line(s) at the entrance protector; these are sometimes seen in some telcos. Basically, they provide functions such as party ANI on multi-party lines, remote disconnect (for testing or (click!) non-payment), or half ringers (the most common -- they prevent ringing continuity failures on switches like ESS when there are no phones hooked to the line when it rings). MTU terminals are often locked. Single Pair Station Protector ----------------------------- There's really not much to say about this terminal. Basically, it takes the service or drop wire and connects it to the inside wire in a single line residence (houses with 2 lines will have 2 of these). These are at every house on an outside wall or basement, and there are two main types: the Western Electric 123 (with a "150-type" rubber cover), and the old WE 305 and new AT&T 200 Network interface (metal and plastic, respectively). These terminals have one binding post pair and they will have either gas discharge tubes or carbon blocks to protect the line from lightning or excess current. Obviously, there is no BP number (you just have to visually trace the drop wire to find the protector). This is also the demarcation point marking the end of the telco's responsibility, as well as the end of our tour. ******************** Bell System Standard Color Code Use: ----------------------------------- Take the #, and find it's closest Pair # Tip Ring multiple of 5. Use that number to find ----------------------------------- the Tip color, and the remainder to find 01-05 White Blue the Ring color (remainder 0 = Slate). 06-10 Red Orange (e.g. Pair #1 = White/Brown, Pair #14 = 11-15 Black Green Black/Brown, Pair #24 = Violet/Brown). 16-20 Yellow Brown 21-25 Violet Slate Usually if a color code is needed (such as in a splice case) you can get it from LAC or the testboard; if it's really essential, it will be in LMOS as well. This color code is also used a lot on cable ties (usually with white stripes and ring colors only), although these are often used randomly. --------- Test Sets --------- This is the "right hand" of both the professional and the amatuer lineman. Basically, it is a customized portable telephone which is designed to be hooked onto raw cable terminals in the field and used to monitor the line, talk, or dial out. The monitor function is usually the main difference between the "butt-in" test set and the normal phone. If you don't have a real test set already, the following circuit can convert a normal $4 made-in- taiwan phone into a working test set. The "all-in-one" handset units without bases are the best (I tend to like QUIK's and GTE Flip Phone II's). Anyway- OFFICIAL Agent 04 Generic Test Set Modification (tm) Ring >---------------------------------> to "test set" phone Tip >------! SPST Switch !--------> !-----/ ----------! >from !-------/!/!/!/!--! C = 0.22 uF 200 WVDC Mylar cable pair ! C R ! R = 10 kOhm 1/2 W (alligators) !--! (------------! SPST = Talk / Monitor When SPST is closed, you are in talk mode; when you lift the switch- hook on the "test set" phone, you will get a dial tone as if you were a standard extension of the line you are on. You will be able to dial out and receive calls. When the SPST is opened, the resistor and capacitor are no longer shunted, and they become part of the telephone circuit. When you lift the switchhook on the test set, you will not receive dial tone, due to the fact that the cap blocks DC, and the resistor passes less than 4 mA nominally (far below the amount necessary to saturate the supervisory ferrod on ESS or close the line relay on any other switch). However, you will be able to silently monitor all audio on the line. The cap reactance + the phone's impedance insure that you won't cut the signal too much on the phone line, which might cause a noticeable change (..expedite the shock force, SOMEONE'S ON MY LINE!!). It's also good to have a VOM handy when working outside to rapidly check for active lines or supervision states. Also, you can buy test equipment from these companies: Techni Tool - 5 Apollo Road, Box 368. Plymouth Meeting, PA. 19462. Specialized Products Company - 2117 W. Walnut Hill Lane, Irving, TX. 75229. ******************** I am not going to include a disclaimer, because a true communications hobbyist does not abuse nor does he tamper with something he doesn't under- stand. This article is intended as a reference guide for responsible people. Also, this article was written mainly from first-hand experience and information gained from maintenance technicians, test boards, as well as technical literature, so it is as accurate as possible. Keep in mind that it is mainly centered upon the area served by Pacific Telephone, so there may be some differences in the loop plant of your area. I would be happy to answer the questions of anyone interested, so feel free to contact me c/o the Technical Journal regarding anything in this article or on related topics such as ESS, loop electronics, telephone surveillance / countersurveillance, etc. I hope the article was informative. -------------------------------- Written by: Phucked Agent 04 The Legion Of Doom! -------------------------------- Please - Por Favor - Bitte - Veuillez! ** Do not edit, abridge, fold, spindle, or mutilate.