[VoIP] Oslo phone

[Russ Price]

Steph Kerman wrote:
> If there is leakage you will be able to see that by placing a DMM set to 
> DC mA in series during ringing.  The DMM should register zero during the 
> silent intervals.  In theory it should register zero during the ringing 
> intervals too but some DMMs do not behave well below 60 Hz so it may 
> thrash around, which would be a false indication.  If it registers zero 
> during ringing that would be a reliable indication that there is no 
> leakage problem.

I'll need to get my meter - I left it at work.

> Most likely if it does have too low an impedance for the channel bank 
> you can put a resistor equal to the DC resistance of the ringer in 
> series with it and it will still ring adequately without tripping 
> ringing.  What is the resistance of the ringer coil and the series 
> capacitance value? 

The markings on the ringer are too faded to discern. The capacitor is 
marked as 0.5 microfarads, and it appears to be a double unit with three 
wires going in, two soldered to individual terminals and one soldered to 
two terminals via a soldered jumper.

The wires to the coil, ringer, and capacitor are bundled together with 
twine into an ostentatiously neat cable, so it's difficult to tell which 
wire goes where.  I'll have to open it up again - the terminals have 
various markings (but I don't understand Norwegian).

> What model Oslo phone is it?  There are modern ones and very antique 
> ones such as were used on the first WECo Rotary offices.  These have the 
> 7001 type dial with 0 and 1 holes at the bottom and a number plate which 
> rotates with the finger wheel.

This one is an Elektrisk Bureau phone (based on the EB logo marked on 
the capacitor), model number unknown, shaped like a rectangular box with 
a cradle on top, and the dial is mounted on the cradle.  The dial's not 
a 7001; most likely it's an early Ericsson dial with the Oslo layout. 
The zero is at 6 o'clock like an AE or BPO dial, there's a very faint 
winding sound as I pull the dial back to the fingerstop, and when the 
dial returns I can hear clicketyclicketyclick much like early WE dials, 
with the governor making a slight buzz like an AE dial.

	Russ
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