Julian's Phone Cabling Notes, for German, American, & British Interconnection. http://www.berklix.com/~jhs/standards/phone Tabs: If your browser does not represent a tab character as 8 spaces, diagrams in this file wont align properly, ie vertical pipe symbols '|' in these next 2 lines should align: | | |-------| If you are using Unix vi or similar, use: :se ts=8 See Also: http://www.berklix.com/~jhs/standards/rs232.v24 http://www.berklix.com/~jhs/src/bsd/fixes/FreeBSD/src/jhs/etc/devd/berklix.conf Voltages & Impedances (@ 2016-12-09): http://www.hermonlabs.com/products/innerData/pdf/Analog%20Telephony%20Overview.pdf Plugs & Sockets: https://de.wikipedia.org/wiki/Telekommunikations-Anschluss-Einheit https://en.wikipedia.org/wiki/British_telephone_socket https://en.wikipedia.org/wiki/Modular_connector#6P4C https://en.wikipedia.org/wiki/Registered_jack#RJ45 Wiring Precepts: Privacy/Sharing: German: Lifting handset on a fax machine plugged into an N socket probably interrupts the signal from being passed further to a phone plugged in to middle F socket of a triple socket. Each device may (only if a 6 pin plug And cable) pass signal back to next device, until a handset is lifted. (Can be wired around of course) British: Allow multiple handsets to be lifted simultaneously for party calls. I have modified much of my German socketry to allow party calls. Ringing: Americans ring without earth. British ring with earth. Germans ring without earth. 2 Signal lines on a USA western connector: American: use center 2 British: not the same as American. German: inner 2 Circuit Diagrams Here: Left-Right Aspect: Sockets are viewed as if from external world into wall, or into equipment with a socket. Plugs are viewed looking along cable toward plug further away. (or for German plugs (that have cable at right angles to contact), looking with eyes nearer blank surface of plug, & metal contacts further away, toward a socket on a wall ). So plugs & sockets are draw to match. No idea if this is how manufacturer catalogues present products. My Symbols: # Plastic edge. 0 Plastic moulding slot, digit '0' to show no material ie hole. X Metal contact, X probably to show junction of contacts. [] Metal contacts in a German socket, spring loaded & contact adjacent contact unless a plug is pushed in to disconnect them. <> Locator/polariser lugs, protruding on a German phone plug. ! Indicate supplied wires in a socketas sold, additional to pcb ^ Continuity when no plug is inserted (ie spring loaded pins within the socket that touch, until an inserted plug seperates) V As '^' but with a connecting soldered bridge added by JHS@. Wires Cross ? Or Join ? : As per IEE/BT/etc conventions in use back to at least 1975, (invented pre computer, to cope with blurry blueprints & pencils, & equally appropriate to this Ascii art), where lines cross: 2 wires cross with No connection below: | --------+---- | 2 wires With connection below : | --------+-+--- | Deutsche Telekom Naming Convention: Socket Type Name: ADo pre 1987 = Anschlussdose TAE new 1987 = Telekommunikations-Anschluss-Einheit Letter Embossed Above Each Socket: N = Nicht- fernmeld- apparat = Non phone = Answerphone F = Fern- meld- apparat = Phone Wecker = Bell Erd = Earth =============================================================================== USA Western Crossed System (some normal cables inc. my coiled springy cables) Also Long white cable purchased by JHS@. Also US Robotics Modem has 2 sockets (1 for phone, 1 for line). the connections are crossed, as below. (Ex Sanyo Answerphone TAS 3100, 2 sockets added by JHS@ were wired by me crossed, signal tapped off centre 2.) ###### ######### ######### # 0 X X X X 0 # Western Socket ###################### | | | | \ \ / / \ \/ / \ /\ / X X / \/ \ | /\ | | / \ | \/ \/ /\ /\ / \ | \ | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Socket ###################### =============================================================================== USA Western Straight, not crossed System (some purchased cables inc. Long grey 2 core cable that came with http://tv-silencer.com/ ###### ######### ######### # 0 X X X X 0 # Western Socket ###################### | | | | | | | | ###### ######### ######### # 0 X X X X 0 # Western Socket ###################### =============================================================================== USA Western Double & Triple USA/Western sockets (as purchased from Hartnagel schiller str, cream coloured plastic,) are (all 3 sockets) wired straight, not crossed. 2 x Double socket + 1 plug with push release lever: Straight 4 wire =============================================================================== USA Western Double socket + 1 plug + push release lever, labelled L1 L2 ###### ######### ######### # 0 X X X X 0 # Western Plug ###################### | | +--+--+---------------------+ | | | | | | | +------------------+--+ | | | | | | | ###### | ###### ######### ######### ######### ######### # 0 X X X X 0 # # 0 X X X X 0 # Western Sockets ###################### ###################### L1 L2 =============================================================================== USA Western Double Socket (circuit drawn by me on side) ###### ######### ######### # 0 X X X X 0 # Western Socket ###################### \ / \ / \ / \ / ###### ######### ######### # 0 X X X X 0 # Western Socket ###################### =============================================================================== USA Western Double Socket (normal straight) ###### ######### ######### # 0 X X X X 0 # Western Socket ###################### | | | | | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Socket ###################### =============================================================================== USA Western Extender With Plug & Socket, Socket is black +------------------ Grey | +--------------- Pink | | +------------ Yellow | | | +--------- Green | | | | +------ Brown | | | | | +--- White | | ###### | | ######### ######### # 0 X X X X 0 # Western Socket 6 Pin Pre-Wired ###################### | | | | | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Plug I added, Only 4 pin ###################### | | | | | | | +------ Brown | | +--------- Green | +------------ Yellow +--------------- Pink =============================================================================== White Deutsche Telekom plug with Western Socket, Converter marked "DSL", to fit on Y combi cable of a Fritz 7490 DSL Router. Also same for un-expected cable with 2nd Fritz 7490 cable with Deutsche Telekom plug & Western plug. ####### Plug # F # #3] [4# # # +----#2] 5# | # # | +--#1] 6# | | <# #> | | ####### | +-----+ +----+ | Green | | Red ###### ############ ############ # 0 0 0 X X 0 0 0 # Western Plug 8 slot size ############################ =============================================================================== Black Deutsche Telekom plug with Western Socket, Converter marked "TEL", to fit on Y combi cable of a Fritz 7490 DSL Router ####### Plug # F # #3] [4# Green # # +--------#2] 5# | # # | +--#1] 6# | | <# #> | | ####### | +--------------+ | Red | | ###### ############ ############ # X 0 0 0 0 0 0 X # Western Plug 8 slot size ############################ =============================================================================== Telekom Y Cable from Fritz 7490 DSL Router Colours Approximate A=Red Orange, B=Green, C=Orange, D=Blue+White, E=Blue, F=Orange, G=Green, H=Green. ###### ############ ############ Router, 259 on plug. # A B C D E F G H # Western Plugs 8 slot size. ############################ | | | | | | | | +-------+--+--+--+ | | | +-------+ | +----+--+--+-----+ +--+----------+--------+ | | | | | +-------+ | | | | | +--+-------------------+--+--+ | | | | +----------+ | | | | | | +----------------+-----+ | | | | ###### | | ###### | | ############ ############ ############ ############ # 0 0 0 X X 0 0 0 #White # X 0 X X X X 0 X # Black ############################DSL ############################ Tel =============================================================================== Weird: German Non Phone (N) Plug to Western Plug Tan colour cable, welded plastic, inherited by JHS@: What this weird config is I don't know, so I've marked cable as weird, should work on a USA 2 wire device though. Possibly not for a phone as it uses all 6 poles ? Maybe it was for Ethernet ? https://de.wikipedia.org/wiki/Ethernet-Anschlussdose +----------------------+ +-+--------------------+ | | |+-----------------+ | | | || ####### | | | Plug | || # N # | | | | |+--------#3] [4#--+-+ | | | <# #> | | | | +-----#2] 5#--+-+ | | | | # # | | | | | | +--#1] 6#--+-+-+ | | | | # # | | | | | | ####### | | | | \ / | | | | \/ +-----+ | | \ /\ | | | \ / \ +--+-------+ | | | | | | | | ###### | | ######### ######### # X X X X X X # Western Plug ###################### =============================================================================== German Non Phone (N) Plug to Western Plug, all 6 connectors in use, Grey Cable +-----------------+ | ####### | | # N # | +--+--------#3] [4#--+-+ | | <# #> | | | | +-----#2] 5#--+ | | | | # # | | | | +--#1] 6#--+ | | | | | # # | | | | | | ####### | | | | | | | | | | | | +--------+ | | | | | | +-------+ | | | | | | | | ###### | | ######### ######### # X X X X X X # Western Plug ###################### =============================================================================== German Non Phone (N) Plug to Western Plug, all 6 connectors in use, 2 x Black Cables, Grey inserts in German plugs. +-----------------+ | ####### | | # N # | +--+--------#3] [4#--+---+ | | <# #> | | | | +-----#2] 5#--+-+ | | | | # # | | | | | | +--#1] 6#--+ | | | | | | # # | | | | | | ####### | | | | | | | | | | | | +----------+ | | | | | | +---------+ | | | | | | | | ###### | | ######### ######### # X X X X X X # Western Plug ###################### =============================================================================== German Non Phone (N) Plug to Western Plug, all 6 connectors in use, 1 x Black Cable, Black insert in German plug. +--------------------+ | ####### | | # N # | | +--------#3] [4#--+-+ | | <# #> | | | | +-----#2] 5#--+ | | | | # # | | | | +--#1] 6#--+ | | | | | # # | | | | | | ####### | | | | | | +-----+ | | | | | | | | | | | +--+-------+ | | | | | | | | ###### | | ######### ######### # X X X X X X # Western Plug ###################### =============================================================================== German Phone (F) Plug to Western Plug Cable purchased by JHS@: ####### Plug # F # +--------#3] [4#--+ | # # | | +-----#2] 5# | | | # # | | | +--#1] 6# | | | | <# #> | | | | ####### | | | | | | | | +--------+ | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Plug ###################### =============================================================================== German Phone (F) Socket to Western Plug Inherited by JHS@, allows binatone & Megaset to work on PBX: ####### Plug # F # +--------#3] [4#--+ | # # | | +-----#2]^[5# | | | # # | | | +--#1]^[6# | | | | <# #> | | | | ####### | | | | | | | | +--------+ | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Plug ###################### w g b y white green brown yellow =============================================================================== German Phone (F) Plug to Western Plug as supplied connected to DT Signo 1 Phone Phone does not work if this cable is removed & a western-western is used to connect phone to PBX. Phone did work (ie dial tone heard) if Grey Cable from BT memory phone was temporarily inserted. Cable (when borrowed) also provided a dial tone on Megaset 930 ####### Plug # F # (Wecker) +----------#3] [4#--+ (Erd) | # # | (Lb) | +----#2] 5# | (b2) | | # # | (La) +--+-----+----#1] 6# | (a2) | | | <# #> | | | | ####### | | | +--+-------------+ | | | | | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Plug ###################### 6 5 4 3 2 1 (numbers on this line derived from Megaset 930) =============================================================================== German Phone Socket (N) on black cable | Black Cable | ####### Socket # N # Green --#3] [4#-- Yellow <# #> Brown --#2]^[5#-- Grey # # White --#1]^[6#-- Pink # # ####### =============================================================================== JHS@ Built Converter to fit between PBX & Megaset 930, that if cascaded onto a normal ["German Phone (F) Plug to Western Plug" (as used for USA stuff)] would also be same pin out for use with a Megaset Yellow, Green, Brown, White ###### ######### ######### # 0 X X X X 0 # Western Plug Short cable ###################### (connect this end to a cable with a | | | | german plug one end, & a western | \ / | for a USA appliance the other end). | /\ | \ / \ / \/ \/ /\ /\ / \ / | | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Plug Long cable ###################### (connect this end to Megaset 930) Yellow, Green, Red, Black =============================================================================== German Non-Phone (N) Plug to Western Plug Cable purchased by JHS@: Grey plug, silver cable, 2 wire) ( At 2017-02 I have 3 N plugs with just 2 wire cables, they all have the 1-6 & 2-5 connections inside plug, seems to be systematic ). ####### Plug # N # #3 4# <# #> +-----#2]-[5# | # # | +--#1]-[6# | | # # | | ####### | | ###### ######### ######### # 0 0 X X 0 0 # Western Plug ###################### =============================================================================== German Non-Phone (N) Plug to 2 Western Plugs "Doppel Anschlusskabel fuer import modems und import telefone zugleich TAE-Stecker an 2 x RJ11-Stecker (6P4C) Codierung = TAE/N, Modem=durchgeschleift Manufacturer: TS-Elektronik Art Nr T2AA-05" (From Todd) ####### Plug # N # #3 4# <# #> +--#2] [5#---------------+ | # # | +--+--#1] [6#---------------+-+ | | # # | | | | ####### | | | | | | White ###### ###### Black Cable ######### ######### ######### ######### Cable Western # 0 0 X X 0 0 # # 0 0 X X 0 0 # Western Plug ###################### ###################### Plug =============================================================================== Siemens Megaset 930 Radio Phone page 26: Belegung der Telefonanschlussschnur 6 Nicht belegt 5 La gelb 4 W grun 3 E braun 2 Lb weiss 1 nicht belegt =============================================================================== BT To Western, black cable, as found 2017-01 between Thomson WPJ530U Wireless Phone Socket System & Amstrad DRX780UK-C BSkyB 14068 ###################### ## # 0 X X X X 0 # ## BT Plug # # ## ###################### ## \ / \ / \/ \/ /\ /\ / \ / \ | ###### | ######### ######### # 0 X X X X 0 # Western Plug ###################### Y G R B e r e l l e d a l e c o n k w Voltages: +50 0 =============================================================================== BT To Western, another flat black cable measured 2017-01 ###################### ## # 0 X X X X 0 # ## BT Plug # # ## ###################### ## \ / \ / \ / ###### ######### ######### # 0 X X X X 0 # Western Plug ###################### G R r e e d e n =============================================================================== Cable (black, coiled) between Headset Phone & BT Plug long retainer tag, designed to be removed, Phone works (rings even) if this cable is removed & a western-western is used to connect phone to PBX. ###################### ## # 0 X X X X 0 # ## BT Plug # # ## ###################### ## \ / \ / \ / ###### ######### ######### # 0 X X X X 0 # Western Plug ###################### = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Notes on audio part of headset phone: Double CoAx Cable Between Headset phone & Headset Tip of plug: Ear Piece (Mono) Aprox 35 Ohm on replacement unit. Mid shank: Microphone Aprox 1500 Ohm Top of shank: Earth X 2 -------------------- Other Walkman style headphones: Tip of plug: Left Mid shank: Right Top of shank: Earth Common --------- Grey mono 8 Mel Orange Mono Plug 105 No foam mono: 33 Pan Am 270 Purple plastic 33 Red+Black foam 15 Sony 33 White mono 8 =============================================================================== Cable (grey) from British Telecom 16 memory phone short retainer tag, designed not to be removed, Phone does not work if this cable is removed & a western-western is used to connect phone to PBX. ###################### ## # 0 X X X X 0 # ## BT Plug # # ## ###################### ## | | | | | | | | | ###### | ######### ######### # 0 X X X X 0 # Western Plug ###################### =============================================================================== BT Sockets ###################### ## # 0 X X X X 0 # ## # # ## ###################### ## | | | | | | | Red | | Blue | Green White - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Headset Phone Only works on red & white. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Previous usage: red & blue Loud dial tone between Red & White Quiet dial tone between Red & Blue BT Slim Phone Of the red white green blue wires, only 2 pairs present an audible dial tone when rest switches are simultaneously pressed: red + white 7.5K Up o/c down red + blue 50K up o/c down red + blue was selected as it presents a higher impedance less likely to be detected by the post, however bell pulses are heard on the main (old ) phone, & meter on old phone does not allways pulse properly for outgoing calls made from the extension. =============================================================================== NFF EXPANSION BOX for MK (as purchased, + Western Socket for answerphone added by JHS@) (cloned & BT socket added to my clone by JHS@ as shown in (BT )) ####### Plug # F # Wecker +--#3] [4#--+ Erd | # # | (BT White) Lb +--+--#2] 5# | b2 | | # # | (BT Red) La +--+--+--#1] 6# | a2 | | | <# #> | | | | ####### | | | | +--------+ | | | | ###################### Screw Block # 1 2 3 4 5 6 # 1=White, 2=Brown, 3=Green, 3=Yellow ###################### La Lb W E b2 a2 | | | | | | +-----------+ | | | | +-------+ | +------------+ | | +--------+ | | | | | | | | | +--+--+---------+ | | | | | | | | | | | +----------+--+ | | | | | | ####### | | ####### | | | ####### Triple Socket | | | # N # | | # F # | | | # F # | | +--#3] [4#-+ +---#3] [4#--+ | | +------#3] [4#------+ | | <# #> # # | | | # # | | +----#2]^[5#--------#2]^[5#----+ | | +----#2]^[5#----+ | | ! # # # # | | | # # | | +-+----#1]^[6#--------#1]^[6#------+ | | +--#1]^[6#--+ | | ! ! # # <# #> | | | <# #> | | | ! ! ####### ####### | | | ####### | | | ! ! +------------------------+-+-+-----------+ | | ! ! | +---------------------+-+-+-------------+ | ! ! | | +------------------+-+-+---------------+ ! ! | | | +---------------+ | | ! +---------+--+--+--+--+--------------+ | +-----------+--+--+--+--+--+-------------+ | | | | | | ###################### # 6 5 4 3 2 1 # Screw block ###################### | | ###### ######### ######### # 0 0 X X 0 0 # Western Socket ###################### =============================================================================== https://de.wikipedia.org/wiki/Telekommunikations-Anschluss-Einheit NFN: "Gängigste Variante. Vor die mittlere Buchse (F) sind beide N-Buchsen geschaltet." NF/F: Zwei a/b-Anschlüsse, für zwei unabhängig beschaltete F-Geräte, vor die mittlere (F-)Buchse ist eine N-Buchse geschaltet =============================================================================== NFN TRIPLE SOCKET as installed by D.Telekom 1993 (sleek socket) ###################### 1: 0V Plain Line # 1 2 3 4 5 6 # 2: +56V Dashed ###################### Terminator ###################### Package # 1 2 3 4 5 6 # ###################### | | +--------- - - ------ | | Broken Link | _+_ | +-------+ | \ / +-------+ +470K +---------------+ -+- +-------+ | | Diode: PH13D ~800 ohm @ ~5V | +----------------------------------+ ###################### Screw Block # 1 2 3 4 5 6 # ###################### La Lb W E b2 a2 | | | | | | +-----------+ | | | | +-------+ | +------------+ | | +--------+ | | | +-------------+ | | | | | | +--+--+---------x-+-+----------------+ | | | | +------------+-+-+----+ | | | | | | | | | | | | | | ####### | | ####### | | | | ####### | | | | # N # | | # F # | | | | # N # | | | +--#3] [4#-+ \----#3] [4#-+ | | +--#3] [4#--+ | | <# #> # # | | <# #> | +----#2]^[5#---+ +---#2]^[5#---+ | +---#2]^[5#---+ | # # | | # # | | # # | +------#1]^[6#-\ | | +-#1]^[6#-----+ | +-#1]^[6#-+ | # # | | | | <# #> | | # # | | ####### | | | | ####### | | ####### | | | | | +-----------------+-+---------+ | | | +-------------------+-+-----------+ | +---------------------+ | +-------------------------+ 'x' above is an assumed correcion from '-' 2017-01 =============================================================================== NFN TRIPLE SOCKET (Ugly) as installed by D. Telekom 1995 With label >ABS< on front, & label >ABS< DBP T on back ###################### 1: 48V Red Line # 1 2 3 4 5 6 # 2: 0V Blue ###################### No removable Terminator Pack (cable push fit, so nowhere to screw in terminator) ###################### IDC Block # 1 22 33 4 5 6 # 8 connectors: 2 for #2 & #3 ###################### | | | | | | +-----------+ | | | | +--------+ | +------------+ | | +---------+ | | | +-------------+ | | | | | | +--|--+----------+-+-+--------------+ | | | | +-------------+-+-+---+ | | | | ####### | | ####### | | | | ####### | | | | # N # | | # F # | | | | # N # | | | +--#3] [4#-+ +-----#3] [4#-+ | | +--#3] [4#-+ | | <# #> # # | | <# #> | +----#2]^[5#---+ +----#2]^[5#---+ | +---#2]^[5#---+ | | # # | | # # | | # # | +-+----#1]^[6#-+ | | +--#1]^[6#-----+ | +-#1]^[6#-+ | | | # # | | | | <# #> | | # # | | | | ####### | | | | ####### | | ####### | | | | | /| | | | +-----------------+-+---------+ | | +--|< |-| | | +-------------------+-+-----------+ | | \| | | | | | | ____ | | +---------------------+ | +--|____|-+ +-------------------------+ Diode: 460K @ .12V, Resistor 470K No diode or resistor on socket bought in Aachen Jan 2000. Socket leaflet says power off devices before sticking in socket. =============================================================================== Aachen from memory 2017-01, Wall, Left to right: N Fall Alert Caller gone @ 2017 F Phone (Radio linked DECT) N Anwerphone & Fax =============================================================================== F plug to NFN TRIPLE SOCKET (Beveled 45 deg. corners) 2017-02 Labelled AAC/JHS before later sending to Aachen for TV silencer. ####### Plug # F # +--#3] [4#--+ | # # | +--+--#2] [5# | | | # # | +--+--+--#1] [6# | | | | <# #> | | | | ####### | | | | +--------+ | | | | ###################### Soldered # 1 2 3 4 5 6 # ###################### | | | | +-----------+ | | | | +------------+ | | | | +-------------+ | | | | | | | | | +--+--+----------+----------------+ | | | | | | | | | | | +-------------+----+ | | | | ####### | | ####### | | ####### | | | | # N # | | # F # | | # N # | | | +--#3] [4#-+ +-----#3] [4#-+ +---#3] [4#-+ | | <# #> # # <# #> | +----#2]^[5#---+ +----#2]^[5# +---#2]^[5#---+ | # # | | # # | # # | +------#1]^[6#-+ | | +--#1]^[6# | +-#1]^[6#-+ | # # | | | | <# #> | | # # | | ####### | | | | ####### | | ####### | | | | | +---------------+-+---------+ | | | +-----------------+-+-----------+ | | | | | +-------------------+ | +-----------------------+ =============================================================================== Tevion ARB781 Answerphone booklet P. 22 says if an NFN socket, use rightmost N. =============================================================================== Philips Fax @ A&R P.8 says use left N, avoid adaptors, distributors, extenders. From another extension, *5 Start fax reception. If picked up phone & then realise its a fax: ** Stop fax reception. If on phone, then fax starts (maybe time delayed transmit). =============================================================================== I used to have -ve on pin 1 on MK@ POTS line & on My 6 digit POTS original line, so I swopped my 7 digit fax line to same MK@ & JHS@ POTS lines had ~56V, my 7 digit fax line less. =============================================================================== German non public plug, large size, ~2cm wide, to Phone With Meter As installed by DT contracted technician. | | Telekom Cable, to a & b | | ###### | W = Wecker = Bell, E = Erd = Earth ##### ##### # E W b a # Socket (non public type) ############## ###### ##### ##### # 4 3 2 1 # Plug (non public type) to phone with meter ############## | | | | | | 4=Unused, 3=Green, 2=Brown, 1=White. Dial Tone between 1 & 2 ------------------------------------------------------------------------------- German Phone (F) Plug to German Plug (non public, large size, ~2cm wide) Cable purchased by JHS@: ####### Plug # F # +--------#3] [4#--+ | # # | | +-----#2] 5# | (secondary color would be brown) | | # # | | | +--#1] 6# | (secondary color would be green) | | | <# #> | | | | ####### | | | | | +--+--+--+-----------+ | | | | | ###### | ##### ##### # 4 3 2 1 # Plug ############## 4=Yellow, 3=Green, 2=Brown, 1=White. =============================================================================== ISDN: NTBA-TK & NTBA-PC cables are 4 wire straight. There's about 97V on my ISDN line, whether or not the NTBA is connected. (I am suprised, I thought phones worked at 50, I must check that JJLATER). My black 7 way S0 block has all 7 sockets wired identically, with a 100 ohm between outer conductors, & another 100 ohm between inner 2 conductors. (Bought from Hartnagel in green cardboard box) Up to 150m total length, with up to 8 taps along the way, with a maximum tap length of 1m, or alternatively up to 800m with no taps. =============================================================================== For DSL Spliters See Also http://www.berklix.com/~jhs/src/bsd/jhs/bin/public/phone/routers.html