BL4CKM1LK teleph0nics [ http://hybrid.dtmf.org ] Digital Access Carrier System DACS by hybrid How did I get this info? -- Well the truth is, as a young child I was abducted by extra terrestrial biological entitys who hardwired microchips in my brain that allow me to intercept the thoughts of telecommunications engineers via ESP.. I was told to gather intricate information about the planet Earth's international PSTN, so when my people from the distant world of xinbin come to inhabit the planet, they can use the information I have transmitted to them from the microchips in my brain as a means to take over our communication networks... er, shit, thats not rite (better lay off the caffiene for a bit).. What I ment to say was, a friend of mine werks for BT, and gave me some nice info on DACS :) -werd Introduction. Digital Access Carrier System is used by British Telecom to transform one residential line into two seperate lines without actually installing an additional trunk pair. The idea of DACS is very similar to the design and implementation of the WB9OO unit used in the past (http://hybrid.dtmf.org/ files/hybrid-files/wb900.txt). The DACS system is becomming increasingly popluar in the UK beacuse more and more people are requesting additional lines, usually for net access. Digital Access Carrier System _____________ _____________ B1 | | | | B1 -------------O | single pair of | O------------- | | wires (trunk) | | analogue | E.U O==================O E.U | analogue | | digital | | -------------O | | O------------- B2 |_____________| |_____________| B2 The chances are, if you order another line from BT, they will simply multiplex your existing line into 2 seperate carriers. Think about it.. if you have one line operating on a dedicated carrier, then the line is multiplexed into 2 serperate carriers, the bandwith will be cut in half. To this date, BT are encouraging its customers to join the 'BT SuperHighway' by installing a second line.. What BT dont tell you is that you will only be able to get a maximum of 28.8bps from your 'second' line. In this file, I'll look into the DACS carrier system in detail, aswell as ways to determine what kind of trunk installation you have if you have ordered a second line from BT. Werd, enjoy the file.. DACS II The origional DACS system had limited capabilitys, and did not allow the customer to have CLASS services on their line. The newer DACS implementation is called DACS II and allows a slightly more advanced service to customers. Now people with DACSII units on their line, have access to CLASS (Customer Loop Access Signalling System). The new DACS hardware, allows customers lines to have K Break (Disconnect Clear), aswell as common services such as CLI, which where previously unavailable to DACS I customers. At the eXchange All exchanges have a database of different customers who have been fitted with the DACS equipment. Some of the commands used on the CSS database at the local terminating exchange are as follows: DISPLAY FRAME TERMINATION RANGE (to see if DACS equipment is fitted to the exchange) DISPLAY FRAME JUMPER (to determine whether a particular customer is using DACS1 or DACS2) Remote End eXchange records The Local Network Records (CSS/LNR) are modified/editited as follows on the O/S at the exchange: ENTER SHARED USE MODIFY SHARED USE DISPLAY ROUTING INVALID COMMAND Compatability of DACS: GOOD.. The provision of PSTN services when used with only BABT - approved Customer Premises Equipment upto 4 REN. Use of any phone exchange within BT's access network, except the following: Inter working with all BT's remote line test systems Self contained payphones Lines utilising CLASS K Break All modems up to 14.4bit/S working Group 1,2,3 fax machines Video phones BAD.. Earth calling PBX's Equipment that uses SPM (meter pulsed payphones) Private Services ISDN2 Steel joint user poles Certain TXE2 exchanges 300 kilohms loop calling Electricity stations DDI Group 4 fax machines DACS system schematics, diagrams.. Old Jumpering Procedure E L : : _____________ : : _____________ | | : : | | | O-:-----. .-:--O | exchange | O-:---. | | : | | external <------------O sub number | : | | | : | bar pair O------------> | | : | | | : | | cable | | : | | | : | | |_____________| : | | | : |_____________| : | | | : : | | | : : | | | : _____________ : | | | : | | : | | | : | DACS block | : | | | : | | DACS shelf : | | | : | O------------> : | | | : | | : | | | : | T B1 B2 | : | | | : |_____________| : | | | : o o o | | |_______| | | | |________________| | |_______________________| New Jumpering Procedure E L : : _____________ : : _____________ | | : : | | | | : : | DACS B1 B2 | exchange | | : : | | DACS shelf <------------O sub number | : : | O------------> | O---:----------:---|--O B2 | | O---:----------:---|--O B1 | |_____________| : : |_____________| : : : : : : _____________ : : _____________ | | : : | | | DACS trunk | : : | | DACS shelf | | : : | | external <------------O | : : | bar pair O------------> | CH2 | : : | | cable | CH1 O--O---:----------:---O | |_____________| : : |_____________| : : : : E.U Card Setup _________________________________________ .--------. | (O) (O) (O) | | | | | | | | | | | | on | | | 1 | | | | | | | | | off | 8 | | |_____(O)_(O)_____________(O)_(O)_(O)_____| | | | | | | <-- B.E.R connector |________| sw7O9 sw7O3 sw7O6 sw7OO _____ _____ _____ _____ c | | c | | c | | c | | .--------. | : | | : | | : | | : | | | | : | | : | | : | | : | | | | : | | : | | : | | : | | | | : | | : | | : | | : | | | r |_____| r |_____| r |_____| r |_____| | | b2 b1 a3 a1 | | |________| DACS 2A EU SW 1O1 (imp) (class) _____ _____ _____ _____ _____ _____ _____ _____ | | | | | | | | cpx | | | | | | | | | O | | O | | O | | O | 6OO | O | | O | | O | | O | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | en | | | | | | | | |_____| |_____| |_____| |_____| |_____| |_____| |_____| |_____| 1 2 3 4 1 2 3 4 1 SW 1O2 4 _____ _____ _____ _____ | off | | | | | | | | | | | | O | | O | 1Ok | | | on | | | | | | | | | | | | | | O | | O | | | | | 15k |_____| |_____| |_____| |_____| 1 2 1 2 (alarm) (sign) External RU Setup BT66 white B1 O--------------. blue | white | .-------------. | | grey | | | | | | | | | | | | | | | | white | | | B2 O------------. | | | orange | | | | | | | | | | | | O O O | | tail | trunk O MIMIC Resistances switch 5 on (cal) 1k ohm loop _____ _____ | | | | C a | | | | a ______ S o--------O | switch 5 off (ug) | O------------O | S b1 | | 10k ohm -50v leg b2 | | b1 | NTE | o--------O | | O------------O______| T b | | | | b E | O======================O | S | EU O======================O RU | T a | | TRUNK | | a ______ o--------O | | O------------O | A b2 | | | | b2 | NTE | C o--------O | | O------------O______| C b | | | | b E |_____| |_____| S S s/c b1 + b2 10k ohm -50v a leg b2 1k ohm loop b1 or b2 EU fault TRUNK fault customer apps fault Welp, thats it for this DACS oday info. Hope someone can find some use of it, HEH. Big shouts to gr1p, b4b0, 9x, substance, psyclone & GBH krew, tip, jorge, lusta, pbxphreak, bodie, zomba, jasun, oclet, knight, epoc, nou, everyone in #darkcyde, #b4b0, #9x HEH, werd to D4RKCYDE.. 2 years going str0ng. "that ascii took me fuckin ages.." the urls.. http://b4b0.org b4b0 http://darkcyde.phunc.com f41th http://www.ninex.com 9x http://hybrid.dtmf.org BL4CKM1LK hardcore teleph0n1cs.. (GO NOW!) ATE/>exit +++ NO CARRIER