Classic Rotary Phones Forum

Telephone Identification, Repair & Restoration => Technical "Stuff" => Topic started by: TIPandRING on December 27, 2008, 07:27:52 PM

Title: Proper line-in wiring for your telephone
Post by: TIPandRING on December 27, 2008, 07:27:52 PM
As a service to everyone, I'd thought I'd give a quick tutorial on the basics of the demarcation point (point at which telephone service enters you home).  And as an added bonus, discuss the ever-so-important issue of the GROUND connection needed to make an old phone ring.

This unit was actually removed from my house (so this is typical Lincoln Telephone and Telegraph installation circa 1963).

The plywood backing was screwed to a joist near the original fuse box. The house has an aerial drop for phone service so drop entered into the basement.

Reliable (Reliable Electric) Protector R123, the standard of the day...
(http://www.chevelles.com/radiotech/protector.jpg)


Now here's some info on this protector device:
(http://www.chevelles.com/radiotech/protector2.jpg)

A)Acetate-based aerial lead-in wire (2 conductor)
B)Protector block assembly
C)"RING" connection (- Central office power)
D) "GROUND" earth connection
E) "TIP" connection (+ Central office power)
F) Removable screw-in carbon fuse--for lightning and transient protection
G) "Bridle wire"--used in the days before plastic "station wire" was run
H) Ground wire lead--clamped to a nearby cold water pipe or ground rod
I) 3-conductor station wire

With respect to earth ground, the "tip" conductor is a 0 volts potential. The "ring" conductor is at -48 volts potential. The negative voltage was used as the early phone pioneers discovered running a + voltage above earth potential actually caused an electrolysis effect on connections and conductors--they'd corrode much more quickly.  If you take a voltmeter and put the red test lead on the tip connection and the black test lead on the ring connection you'd read +48 VDC.

Now my spheel about the ground connection--not only was this important for lightning protection and transient line surge drain to earth, but was a key element to making the phone ring. Many posts are "I can't get my phone to ring" or the eBay seller saying "everything works, but the phone will not ring for an incoming call"....That's because the yellow wire in the mounting cord is 1/2 of the ringer circuit. In the old days, this was connected back to the ground terminal on the protector--which ultimately lead to earth ground and completed a circuit back to the central office's ring generator that sent out 90 VAC superimposed on the line at approx. 20-30 Hz.

So why's this important?  There's only 2 wires in today's circuitry. TIP and RING. Soooooo. you must either rewire the network inside your phone--move the other ringer wire from the GND/Yellow connection OR do what I do and simply tie the yellow wire in the mounting (base) cord to either the green or the red wire. For example, to get a vintage Automatic Electric (GTE) phone to ring with just 2 wires, you must combine the GREEN tip and the YELLOW ground wire together at the baseboard terminal jack.

The whole idea of even using a 3rd wire at the customers' premises was brought about for party-line ringing where you could connect many more phones one pair of wires but selectively have only one phone ring by alternating tip and ground and ring and ground ringer connections. (other equipment was used as well, but we'll save that for later).

I hope this was informative.

:o
Title: Re: A tutorial on phone connections--Part 1???
Post by: bingster on December 27, 2008, 09:54:48 PM
An excellent and informative post, T&R.  Thanks for that information! :)

I remember back shortly before the breakup, Chesapeake & Potomac came out and bypassed our big old porcelain protector that was installed on a joist in the basement when our house was built in 1936.  They replaced it with a little black protector that looked just like the one in your picture.   They left the old one in place, moving the wires to the new one which they mounted right next to it.  When I left home, I took the old protector, and a few feet of no-longer-used bridle wire (I didn't know it was called that!) as souvenirs.
Title: Re: A tutorial on phone connections--Part 1???
Post by: McHeath on December 27, 2008, 11:35:19 PM
Great post!  As my house was built in 66' it has a protector device very similar to the one you picture.  Ours is in the brick skirting around the house, in a metal box that was built in and has a metal door screwed on.  The service feeds from underground.  I did not know that there were fuses in the device, there are a couple of extras in the box.  Didn't know any of that info about the yellow wire and the ground. 
Title: Re: A tutorial on phone connections--Part 1???
Post by: Dan/Panther on December 28, 2008, 01:40:38 AM
I'm a little confused here. I have no yellow wire hooked up at any point in my phone system, yet by attaching the black ringer wire to the green incoming wire, I get my ringers to work, and now by swiitching a few on the 302's I also get ringers without a yellow wire.
The Verizon guy told me they only use 2 wires now, and they aren't even green and Red anymore they are Blue/White, and Blue I believe he said.
Also I find it doesn't matter which way the red and green are connected. So what's the deal ??? In another post, I think Dennis Markham pointed out that veteran phone techs never heard of polarity in the phone system.

D/P
Title: Re: A tutorial on phone connections--Part 1???
Post by: bingster on December 28, 2008, 03:24:17 AM
Quote from: Dan/Panther on December 28, 2008, 01:40:38 AM
I'm a little confused here. I have no yellow wire hooked up at any point in my phone system, yet by attaching the black ringer wire to the green incoming wire, I get my ringers to work, and now by swiitching a few on the 302's I also get ringers without a yellow wire.
The Verizon guy told me they only use 2 wires now...

;) 'swhat he said:

Quote from: TIPandRING on December 27, 2008, 07:27:52 PMSo why's this important?  There's only 2 wires in today's circuitry. TIP and RING. Soooooo. you must either rewire the network inside your phone--move the other ringer wire from the GND/Yellow connection OR do what I do and simply tie the yellow wire in the mounting (base) cord to either the green or the red wire. For example, to get a vintage Automatic Electric (GTE) phone to ring with just 2 wires, you must combine the GREEN tip and the YELLOW ground wire together at the baseboard terminal jack.

I'm guessing your confusion lies in the yellow in the last sentence referring to the yellow conductor of the mounting cord, rather than the yellow conductor of the station wire.

Incidentally, even though modern techs say they don't use red and green anymore, I'd wager that 95% of all residential telephone wiring uses those two colors.  All the station wire sold in hardware stores uses the old standard colors, too.
Title: Re: A tutorial on phone connections--Part 1???
Post by: Dan/Panther on December 28, 2008, 03:34:54 PM
I need to add that this is on my W.E. 500 phones.

Yes I was referring to the mounting wire. The yellow internal wire in the phone is still connected, to the Red mounting wire at L-2.. The black wire from the ringer was moved to L-1. The G terminal is no longer being used.
The yellow wire at the baseboard terminal jack, is now connected to the green wire.
Maybe my confusion comes from terminology.

Define the following for clarification to me please.

Station Wire, I assume means the wire from the phone company.

Mounting cord, I assume is the cord from the phone to the  Baseboard terminal jack.



D/P
Title: Re: A tutorial on phone connections--Part 1???
Post by: bingster on December 28, 2008, 03:56:20 PM
You have the definitions correct. The yellow conductor of the baseboard station wire is unnecessary, and doesn't figure into the equation at all.  It's the yellow conductor of the phone's mounting cord that's the important thing in T&R's Automatic Electric example, and gets connected under the green screw of the terminal block on the baseboard (along with the green conductor from the mounting cord).
Title: Re: A tutorial on phone connections--Part 1???
Post by: TIPandRING on December 28, 2008, 05:53:39 PM
Yes, sorry for any confusion. The Mounting cord refers to the cord from the back of the phone that connects back to the wall outlet or wall terminal block.

Station wire is the wire that runs all over your house/business/apartment from the demarcation point to each wall terminal block or wall jack.

It's the phone itself you must "modify" to make it ring (at least phones made prior to about 1980). You must move the "ground" wire in the mounting cord to either the TIP connection or the RING connection (based on the manufacturer) at the wall connection to make it ring. OR leave the ground wire "dangle" and trace the ringer connections inside the phone and make the modification inside on the network connections so the bell(s) are tied to TIP and RING without needing the ground connection.

I think I'm gonna make a series of these tutorials (if you guys don't mind) :D  Next up will be wiring and color codes.
Title: Re: A tutorial on phone connections--Part 1???
Post by: Bill on December 29, 2008, 11:46:12 AM
TipAndRing -

Before you move on to Part 2, could I suggest that you edit the original post to incorporate the clarifications that came out in the next 10 posts? That way the original post will become a complete standalone tutorial for that topic, ready for printing and saving.

Thanks

Bill
Title: Re: A tutorial on phone connections--Part #1
Post by: Konrad on January 13, 2009, 01:26:47 AM
Thanks.  I've noticed most home wiring now only has the tip and ring connected and many base cords only have two conductors.  My 1957 vintage 500s work just fine with this setup.  But I have one 500 that's giving me fits and I'll try providing it a ground.
Title: Re: A tutorial on phone connections--Part #1
Post by: bingster on January 13, 2009, 02:59:24 AM
You mean running an actual ground wire to a cold water pipe or something?  I wouldn't advise that.  The post mentions that grounds were necessary a long time ago, but that he phone system today isn't set up to use grounds, and they serve no purpose.

The point of the post is that you may have to move a wire at the terminal block on the baseboard, or inside the phone to get your phone to ring.  No ground required.
Title: Re: A tutorial on phone connections--Part #1
Post by: Sargeguy on January 15, 2009, 09:57:30 PM
Pretty much.  ANd it had my DSL running through it. ::) I have since upgraded to a Leviton structured cable box with a DSL splitter and a base block for 9 phone lines.  There has been a noticeable improvement in the DSL and the ringer efficiancy.  I can get my 202, 302, and 500 all ringing at once.
Title: Re: A tutorial on phone connections--Part #1
Post by: ranch67 on January 25, 2009, 05:16:05 PM
New guy here.
after reading all above posts, couldn't you also move the yellow wire to the green post inside the phone?

i have a 1956 WE model 500 as well. it works, but doesnt ring.
i replaced the original wiring that would go from phone to the baseboard with a modular style.

thanks for the help!


Title: Re: A tutorial on phone connections--Part #1
Post by: TIPandRING on January 25, 2009, 10:33:47 PM
Quote from: ranch67 on January 25, 2009, 05:16:05 PM
New guy here.
after reading all above posts, couldn't you also move the yellow wire to the green post inside the phone?

i have a 1956 WE model 500 as well. it works, but doesnt ring.
i replaced the original wiring that would go from phone to the baseboard with a modular style.

thanks for the help!




Just tying the yellow wire (from the line cord) and the green wire (from the line cord) together inside the phonewill not solve your ringer issue. You'd have to find the wire that comes from the ringer itself and connects under the yellow wire terminal screw (typically black wire from the bell coil) and move that to the green wire terminal.
Title: Re: A tutorial on phone connections--Part #1
Post by: ranch67 on January 25, 2009, 11:13:34 PM
ohhhhhh.
yellow line wire to green post inside phone AND inside phone black wire (from ringer) to green post screw.
i figure i should do this no matter what as i've taken it apart and its big and heavy and in my face. a good thing about phones is they're low voltage.
if i do this, i can move to any phone jack in my house too.

Title: Re: A tutorial on phone connections--Part #1
Post by: TIPandRING on January 25, 2009, 11:17:15 PM
Quote from: ranch67 on January 25, 2009, 11:13:34 PM
ohhhhhh.
yellow line wire to green post inside phone AND inside phone black wire (from ringer) to green post screw.
i figure i should do this no matter what as i've taken it apart and its big and heavy and in my face. a good thing about phones is they're low voltage.
if i do this, i can move to any phone jack in my house too.



NO I  was trying to state that tying the yellow and green wires together inside the phone, will not help.

It's tying the green and yellow together at the baseboard jack that makes the phone ring.  It is by far easier to just leave the connections inside the phone alone. Then when you wire the phone up to the wall jack, or add a modular adapter to the end of the original cord, simply connect the yellow and green wires coming out of the line cord together and put them under the "green" screw at the jack or adapter and the red wire under the "red" screw. Voila! Phone works and it rings.

:D
Title: Bridle wire?
Post by: luns on January 06, 2016, 08:25:27 PM
Quote from: TIPandRING on December 27, 2008, 07:27:52 PM
A)Acetate-based aerial lead-in wire (2 conductor)
G) "Bridle wire"--used in the days before plastic "station wire" was run

Quote from: bingster on December 27, 2008, 09:54:48 PM
When I left home, I took the old protector, and a few feet of no-longer-used bridle wire (I didn't know it was called that!) as souvenirs.

I'm wondering whether this usage of the term 'bridle wire' to refer to twisted triple conductor cord is well established, or if it grew out of a misunderstanding.

My understanding of 'bridle wire' is that it refers to the usage of the wire rather than the type of wire itself (aside from being wire intended for said usage), and refers to wire that hangs loosely between attachment points or occasional support rings (bridle rings). I would think an aerial lead-in would fit this description, but cable draped loosely from hanger to hanger along side a joist should count too. Indeed, the one remaining run of triple-conductor phone line in my parents house, follows a floor joist, loosely threaded through a series of bridle rings; disconnect one end, and you can just pull the whole line out with your bare hands.

Modern day examples:
http://ce.superioressex.com/products/communications/osp-cable/wire/Bridle-Wire/
http://www.cooperindustries.com/content/dam/public/bline/Resources/Library/catalogs/commdata_equipment/commdata_supports/SSF-BridleRings.pdf
Title: Re: Proper line-in wiring for your telephone
Post by: AE_Collector on January 07, 2016, 12:49:13 AM
Here in British Columbia Canada we had 2 conductor non jacketed wire that we called Bridle Wire. Effectively it was jumper wire but had a very tough and fairly thick plastic insulation on each conductor that also likely had UV protection in the plastic. We used this Bridle Wire in outdoor locations on poles between two terminals. These were usually a pole or strand mounted Ready Access (RA) terminal (CO cable) and the terminal on the end of a Figure 8 Drop wire providing service to a building. Bridle wire was the wire run usually in Bridle Rings between these two terminals. Old non jacketed Station Wire may look like Bridle Wire (except that the Station Wire here always had 3 conductors) but we never called this Bridle Wire. It was "Station Wire" or also frequently referred to as "Style" from an older description likely derived from wire names such as "Style A" or "Style B" wire.

Terry
Title: Re: Proper line-in wiring for your telephone
Post by: Babybearjs on January 07, 2016, 08:02:52 PM
Now, I'm totally confused.... you guys are suppose to know this stuff..... the color code has changed but this thread makes no sense... we all know the originalstation wiring was R/G/Y/Blk.... Red=Ring, Grn=Tip, Yel=Gnd. and Black was Aux. when the color code was updated, it went from Grn/Red/Yel/Blk to Blue Blue/Wht and Orange/ Org/Wht.   this is for JUST THE STATION WIRING. as far as the line cord goes, the wiring hasn't changed at all. its still R/G/Y. yellow used to be ground but is not used anymore. so, it stays used, but dead. in the 302, the yellow wire goes to the GND terminal by itself, and does not get used. the Grn/Red wires get connected as usual to the L1/L2 terminals. why this subject is even on here is beyond me..... the wiring has always been simple.... for further info, go to www.wire-your-phones.com for details
Title: Re: Proper line-in wiring for your telephone
Post by: AE_Collector on January 07, 2016, 10:01:53 PM
I think the discussion really started out as an observation about 3 wire line cords and putting the yellow and green together to have the ringer connected. Prior to modular connectors which was also when quite a few more party lines existed, this method was very clever as a phone could be installed as a Provate Line, Party 1 or Party 2 all without having to open the phone up to play with ringer wires inside.

Once modular plugs arrived on the scene this was no longer possible unless wiring was palyed with in the wall jack but wiring shouldn't be messed with there. Jacks should all be standard.

The change in station wire color coding came with the change from individual conductors to twisted pairs as far as I know. Set cords, Jacks and old station wire are all individual conductors and the color code for them is Green, Red, Black, Yellow, White, Blue etc.

Twisted Pairs use the Wh-Bl & Bl-Wh, Wh-Or & Or-Wh, (etc) color code. The Wh-Bl & Bl (solid colored Ring conductor) is really only used sometimes in 4 pair wire as with less than 6 pairs there is no need for the Red, Black, Yellow and Violet colors so the White isn't really needed on the Blue lead.

Terry
Title: Re: Proper line-in wiring for your telephone
Post by: Phonesrfun on January 07, 2016, 10:46:54 PM
Quote from: Babybearjs on January 07, 2016, 08:02:52 PM
Now, I'm totally confused.... you guys are suppose to know this stuff..... the color code has changed but this thread makes no sense... we all know .....

Well, maybe so.  TIPandRING posted the original message 7 years ago and it was a pretty good post.  At that point this forum was only about 4 months into existence and the forum was in need of informative posts like the one he started.  Along came a couple people and expressed their confusion that they did not previously know about the need for a ground wire for divided ringing.  I think that was a great example of what this forum is all about.  Namely education.

OK, so sometimes a thread can go sideways and people have different opinions and experiences when it comes to some things.  Once in a while misinformation has been known to be disseminated.  Lord knows, I have said things here thinking I was absolutely correct, only to be corrected and that too is educational.

I really get a lot from these posts even if it is on a topic that I think I already know everything about. 
Title: Re: Proper line-in wiring for your telephone
Post by: Babybearjs on January 07, 2016, 10:55:43 PM
never hurts to review changes.... its like taking a test.....you have to read up on it to understand the changes.
Title: Re: Proper line-in wiring for your telephone
Post by: kb3pxr on February 28, 2018, 08:20:04 PM
I've always wondered about the yellow ground wire, especially in areas served by independents. While my research indicates yellow was standard in the Bell System, I've seen installations where yellow was not present, but black was. In my own house the original wiring (from when my parents moved in) only had red, green, and black. While black was not connected, was that used for ground in some areas. Also I've seen wiring in GTE territory for pay phones that was the same scheme of red, green, black. Did independents just use black instead?

Also, there is a generation of protector between the one shown in this thread and today's modern network interface. The protector module contains three terminals, two for the line, and one for ground. There are two sets of nuts on the line terminals, the set toward the back is for the incoming line and the set toward the front is for the station. TII still makes these protectors as well. The only major differences between these and the modern NID are the lack of a modular jack or demarcation (no customer side, yet telco tech told my dad in the 90s we could work on that side).
Title: Re: Proper line-in wiring for your telephone
Post by: Babybearjs on February 28, 2018, 10:04:06 PM
 ;D Love the post..... but let me bring you up to speed..... your article talks about the OLD way the phone system used to work.... the red and green have been replaced with blue and white... and the yellow is no longer used. (unless you really need to). the old "reliable" block has been updated to a modern interface that uses gas tube instead of carbon and the polarity still matters. back in the day, one used to be on a PARTYLINE, thus the use of the yellow wire... the ringer was attached to either the green or red and the yellow wire... all phone now are on a single line circuit... now we only use the green and red- or blue and white, which ever the case may be.... and of course since everyone uses a CELL PHONE.... landlines are becoming obsolete.... BUT.... there are still some of us who HATE cell phones and are hold outs for the good old traditional phone service.... or as it used to be called, POTS! (Plain Old Telephone Service, or P-O-T-S) No touchtone, no caller ID no speed dial, no fancy services.... just the dial tone and some long distance.... and a good old ROTARY phone.... ;D ;D ;D The post is appreciated! I love seeing the old stuff....   now, comes the question..... if you live in tornado alley, do you still use this kind of wiring? (or has it all been "Blown Away"..) Lightning is still the enemy of the telephone and in some areas... is pretty active... so... the yellow wire would still have to be used... does this area still wire their phones the old way?
Title: Re: Proper line-in wiring for your telephone
Post by: kb3pxr on February 28, 2018, 11:00:47 PM
There are two wires to the ground terminal in the old system, there is the telephone set ground, but also the earth ground. Lighting protection is provided by the earth ground. There are two types of protection primary, and secondary. The telephone company provides primary protection, the customer provides secondary protection if/when needed.

Primary protection is provided by the protector, in later schemes the drop wire works with the protector to complete the protection. The primary protection is for lightning (except direct hit to the wire, nothing can protect against that), power crosses (power line contacts telephone line) and induction (surge on another wire affects the telephone wire). The older protectors had fuses (the one in the first post had them integrated into the protector modules themselves), newer protectors are fuseless and use the drop cable as a fuse during a cross.

Primary protection is fine UNTIL you start connecting to the telephone network and another system such as the power grid. Answering machines, cordless phones, modems, even high end corded phones can have this problem. Key systems and PBX systems have this as well.

When this type of equipment becomes involved, you now need secondary protection, the FCC actually requires limited secondary protection in the equipment (to protect the phone company's lineman, not your wallet), but additional protection is required. Secondary protection includes overvoltage protection that operates during the short "overshoot" period between the surge starting and the protector operating. Solid state devices clamp the overshoot until the gas tube starts conducting and takes the surge. You need to also consider sneak currents in some cases as well, especially PBX, key, and central office systems. Traditionally this was provided by a fuse or heat coil system where the heat coil would open the line and require replacement. Newer protection modules use a PTC thermistor system or a heat coil system that will actually short the sneak current until the fault clears.
Title: Re: Proper line-in wiring for your telephone
Post by: markosjal on March 03, 2018, 03:08:11 AM
In Mexico there is NO LIGHTNING PROTECTION USED ON COPPER LINES!

Also no ground on CATV coax

I know one guy who Fried every wired device on his network which was connected to a cable modem. He lost like to computers , a multifuncion printer and a VoIP device.

I have looked for anything that looks like telco quality lightning supressors here and no luck. I see some asian cheapies on ebay but not sure if they are worth it.

Ok beseides devided ringing on party lines tip/ground , ring/ground, and bridged , wasnt frequency specific ringing also uses? PArty 1 30 hz and party 2 40 hz ?

It was always my understanding that a telephone ringer circuit is an L/C tank circuit tuned to the 20Hz ringing

I remember many years ago I had a 354 with a Tube in it . As I was very small and did not ubnderstand fully but believe it was part of the ringer circuit. Was this how early frequency ringing was achieved?


Mark

Title: Re: Proper line-in wiring for your telephone
Post by: dsk on March 03, 2018, 06:02:21 AM
In Norway the copper pair is just wired to the first Jack, that acts as the demarcation point. Usually no ground, and no protection as fuses or lightening protection.   If you have a coax no protection, same procedure.  The internet devices and cables as cat 5 or higher may be shielded, but has no connection to ground/earth.  In very old phone installations ground could be used for signalling as in grounded ringing.

dsk
Title: Re: Proper line-in wiring for your telephone
Post by: AE_Collector on March 03, 2018, 08:36:50 AM
I always heard that it was acceptable to have no protector on a communications circuit if it were all underground cableing. But since an underground service could be above ground at other locations as it travelled from CO to subscriber our Telco chose to use protection in both ends of the circuit in all situations.

I wonder if COs have protectors still in locations such as Mexico or Norway that don't use protectors at the subscriber end?

There are many ways used to ring phones on Party lines, one method used different tuned Ringer frequencies in phones on party lines with greater than two parties on the line. This method is primarily associated with Automatic CO's not Manipual CO's. The ringers for two party lines were typically regular SL ringers and were connected tip to ground or ring to ground. If a four party line then all phones had frequency ringers in them, typically 20~ and 30~ Using the tip or ring to ground connections to create the four different scenarios. This method could provide selective ringing to up to about 10 parties typically.

Someone will explain the use of the tube....I don't think it was an alternate way of accomplishing the above but maybe a method required in some circumstances possibly due to distance from the Automatic CO?

Terry

Title: Re: Proper line-in wiring for your telephone
Post by: dsk on March 03, 2018, 08:52:39 AM
Quote from: AE_Collector on March 03, 2018, 08:36:50 AM
I always heard that it was acceptable to have no protector on a communications circuit if it were all underground cableing. But since an underground service could be above ground at other locations as it travelled from CO to subscriber our Telco chose to use protection in both ends of the circuit in all situations.


Terry



They used Krone connectors on poles and probably in CO here they had lists with dual protectors with spark gap.  Like this: http://yuhui.en.hisupplier.com/product-993761-10-Pair-Krone-Protection-Magazine.html (http://yuhui.en.hisupplier.com/product-993761-10-Pair-Krone-Protection-Magazine.html)  This link my die, and I have no pictures  >:(

dsk
Title: Re: Proper line-in wiring for your telephone
Post by: poplar1 on March 03, 2018, 10:35:27 AM
Quote from: AE_Collector on March 03, 2018, 08:36:50 AM

Someone will explain the use of the tube....I don't think it was an alternate way of accomplishing the above but maybe a method required in some circumstances possibly due to distance from the Automatic CO?

4-party selective or 8-party semi-selective using superimposed ringing and  biased ringers and cold cathode tubes. WE 501, WE 306 (H5 tel set mounting),/WE 356. Earlier sets used relays (297G subset). After tubes, diodes used instead:

+ Tip
- Tip
+ Ring
- Ring.    (Not necessarily in that order.)

Title: Re: Proper line-in wiring for your telephone
Post by: AE_Collector on March 03, 2018, 11:25:31 AM
It's still fuzzy but the tube was across the line and the ringer connected to the Tube? Was this to improve the line quality by getting the ringers off the line? We're there different tubes in other parties phones with the tube recognizing when the appropriate ringing was there for the party?

Terry
Title: Re: Proper line-in wiring for your telephone
Post by: kb3pxr on March 06, 2018, 11:18:32 AM
Quote from: AE_Collector on March 03, 2018, 11:25:31 AM
It's still fuzzy but the tube was across the line and the ringer connected to the Tube? Was this to improve the line quality by getting the ringers off the line? We're there different tubes in other parties phones with the tube recognizing when the appropriate ringing was there for the party?

Terry

I'm not too well versed in these circuits, but these weren't that complicated. The only difference between parties was the wiring. There were also solid state variants.

These circuits were effectively diode circuits. If you were tip positive party, ring parties wouldn't reach the circuit and negative tip would be blocked by the tube (or diodes). When positive tip was rung, the tube conducted and allows the current to reach the bell.

In fact, the circuit is so simple that in the Bell System, the test for a bad tube was to simply short the tube pins with a screwdriver and have a ringing test ordered from the CO (either test desk special test number). If the tube was bad the bell would ring with shorted terminals, but not with the circuit normal, if the tube was good (or there were multiple faults), the bell would not ring.

Of course repair service couldn't just jump the bell out of the circuit as the positive and negative selectivity would be lost and other problems such as too many ringers on the line could also result.