GPO 706L not dialing out.

[xantaus]

I've made an attempt at converting a GPO 706L, for which this forum has been invaluable, however I've been unable to dial out.

Ringing and receiving calls is fine. I get a dial tone, but when turning the wheel the dial tone cuts out until the wheel completes its rotation, then returns.

The phone is wired as follows.

From phone handset:

White -> T10
Green -> T2
Red -> T1
Blue -> T3

From Line cord ( to plug)

Green -> T15
Red -> T8
Blue -> T6
White -> T18

From Press switch:

Pink -> T10
Blue -> T2
Brown -> T3
Orange -> T8

From Ringer:

Orange1 -> T4
Orange2 -> T16

Strapped:

T5 -> T6
T16 -> T17 -> T18 -> T19

3.3k ohm resistor:

T4 -> T5


I'd welcome any guidance anyone can offer me!

[Station X]

Put an analogue meter on ohms range across the A & B wires of the phone with it UNPLUGGED. Dial digit '0'. If the dial is working you will see the reading go to almost zero as you wind up the dial. When the dial is released the meter reading should flicker around 2/3rd full scale. The proves that the dial is working. That being the case your TSP probably doesn't accept loop dialling.

If you have only a DMM restrain the dial as it returns and watch to see if the reading goes from short circuit to open circuit.

[julie_m]

Who is your phone company? Does the phone work on another line supplied by a different company?

If you briefly depress and release the hook switch buttons just once, does the dialling tone go away?

Can you go tap ..... tap tap ..... tap tap tap on the switch hook buttons and connect to the speaking clock?

[Station X]

I strongly advise you not to try "tapping up". It's all too easy to dial 112 (The European Emergency Number) in error. If you don't then speak to the operator and assure them that nothing is wrong, the emergency services will turn up at your house and they won't be impressed.

112 is a poor choice for an emergency number where loop disconnect (pulse) dialling is used. It's all to easily simulated by line faults, tree banches contacting open wire and JCBs cutting through cables.

Please keep this thread on topic now. No discussions about the evils of the EU etc. We've heard it all before.

[xantaus]

I currently don't have a multimeter so that test will have to wait until I get one.

Pressing the Hook switch button briefly and once only cuts out the dial tone for the time the button is pressed down.

My phone company is virgin media.

[xantaus]

The dial tone may disappear for half a second more than the switch is pressed down if that makes a difference.

[AndiiT]

Originally Posted by xantaus

...My phone company is virgin media...

Hi,
Although Virgin Media's lines still support pulse dialling, in many areas the type of Switch (Exchange) used can be very fussy about having the correct speed of dial pulse train presented to it, particularly if it is of the Nortel DMS variety.

BTs switches are somewhat more forgiving in this respect, if you know someone who has a BT line you could always try your phone there before looking for a non - existent fault. Stripping the dial and cleaning it may allow the phone to dial out on your Virgin Media line.

Some instructions bout dial maintenance can be found here

Regards
Andrew

[twocvbloke]

Personally, I'd say you have a line that doesn't support Pulse Dialling, before the VM takeover, by brand name you could tell which areas did and didn't have LD functions, now though it's all the same cable co. and puts in a lot of guesswork...

The VM area I'm in does support LD dialling and is forgiving enough that you can hand-dial (tapping the hookswitch), but then it was originally "Nynex" cable, then Cable&Wireless, then NTL: and finally VirginMedia. I think it is predominantly former Telewest (Blueyonder?) areas that have difficulties with LD, and Northumberland looks to fall into the Telewest category...

[xantaus]

I've never used a multimeter before so I'm assuming I'm doing this correctly.

Placed red point to the position marked "A" on the vertical PCB
Placed black point to the position marked "B" on the vertical PCB

Set multimeter to 200ohms setting with points separated it gives a reading of 5.1 and the resistance doesn't change as the dial is moved.

[AndiiT]

Hi,
You don't say whether your meter is an analogue or digital one.

Set the multimeter to the low ohms range and connect one of the leads, it doesn't matter which, to either the Red of the line cord or T8 on the telephone PCB (this is known as the B leg connection) and the other lead to the white of the line cord or T18 of the PCB (the A leg)

With a digital multimeter you should see the display change from infinity to zero Ohms as the dial is rotated towards the finger stop and as the dial is released the reading should vary from zero to infinity as the dial returns.

It is, admittedly, easier to see this on an analogue meter as the needle will flick from infinity to zero in conjunction with the dial pulses.

Regards
Andrew

[xantaus]

Ah using T8 and T18 (why are they called A and B?) I get open circuit normally and low resistance (2.3ohms) while the dial is being used.

I'm using a digital multimeter.

[xantaus]

On dial release it goes straight back to open circuit, if that's helpful.

[DAVEHALL]

Just tried this one - and it works (and I'm on VM).
Connect phone to line. Pick up another handset ,and listen .Dial out on 706- you will hear dial impulses on line if all ok .( I used a cordless on line to listen ,and a switchable good quality phone to dial out)

[twocvbloke]

Originally Posted by DAVEHALL

Just tried this one - and it works (and I'm on VM).
Connect phone to line. Pick up another handset ,and listen .Dial out on 706- you will hear dial impulses on line if all ok .( I used a cordless on line to listen ,and a switchable good quality phone to dial out)

Some cable areas can support LD dialling, other's can't or have very picky LD equipment at the exchange, just saying you're with Virgin Media means nothing, cos before they all merged into that, they were separate franchises (Cable & Wireless, "pure" NTL and Telewest) with different setups for phone, TV and internet...

A good example is most cable areas have Caller ID, the area we're in though doesn't, and they're not planning to install it any time soon, LD works great though, but it changes from franchise to franchise...

[AndiiT]

Originally Posted by xantaus

Ah using T8 and T18 (why are they called A and B?)

A and B are standard telecomms terminology and don't really refer to the terminals, more so the wiring on your incoming exchange line.

The B used to stand for 'Battery' which should be nominally around 50 Volts negative, on an idle line, with respect to the A leg. (see below)

The A leg has been rumoured to stand for 'eArth', but in reality it is not at true earth potential but stands around 4 to 5 volts positive with respect to it.

When idle (i.e. Off hook), BT lines are around 48 Volts and most Virgin media lines (Ex ntl franchises using a Nortel DMS 100 switch or similar) are around 42 Volts across the A and B legs.

Originally Posted by xantaus

I'm using a digital multimeter.

As has been already mentioned an analogue meter would probably give a better indication of whether you dial is operational as the meter needle would 'flick' in sympathy with the dial pulses, which may be too fast for a digital meter to indicate.

Regards

Andrew

[DAVEHALL]

Originally Posted by twocvbloke

Some cable areas can support LD dialling, other's can't or have very picky LD equipment at the exchange, just saying you're with Virgin Media means nothing,

Yep - but you're missing POINT. If LD pulses are heard- means little is wrong with phone. Might mean the area don't support LD, or the pulse ratio is wrong.Most phones DON'T change pulse ratios, unless played with ( or are very old) -that's my experience .Oh- I know certain BT phone systems did output some weird LD con-figs .

[xantaus]

So just to be clear I'm doing this:

1) pick up a working phone (using touch tone).

2) listen to the working phone while picking up the handset on the gpo 706l and dialing random numbers.

I hear a faint crackling on the modern phone, no where near the volume of the dial tone,but audible.

[twocvbloke]

If the sound you're hearing is sort of like a uniform "tapatapatapa" sound, then that's right for a Pulse dial phone...

[xantaus]

Any advance on this point?

I hear the tap tap tap on the phone but dialing out is still impossible, are there any other options or is this due to the exchange not accepting pulse dialing?

If this is the case is there any work around? Or is it a case of change providers or dont use the phone?

[Dave Moll]

The solution may be to purchase and install a pulse-to-tone converter. The one referenced is installed within the 'phone, but they used to have an external unit as well.

I have no connection other than having a 746 with one successfully installed within it.