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Old 27th Dec 2009, 12:01 pm   #31
russell_w_b
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Default Re: Army Field Telephones and Compatibility?

Quote:
Originally Posted by GMB View Post
Could you say how the CB mode works (i.e. what difference is seen on the line)?
A quick look at the diagram for a 'J' suggests that when the 'CB' switch is pulled, it throws the two 500R bell-coils into parallel and removes the 2u bell-capacitor from cct, and so will allow sufficient DC to make a signalling loop to the exchange. The switch is normally out (capacitor in) when waiting for a call, but, when pulled out, will signal DC to the exchange. It must be replaced after 'hanging up'.

Quote:
Originally Posted by GMB View Post
Also, can you have multiple field telephones on the line (when not using a CB exchange)?
Don't see why not - I think I worked out about six would go (type 26A magneto-generator). Bear in mind that the 'J' doesn't have a nice jingly bell; more of a lumpy hammer-action on two bent pieces of metal attached to the case, so using it as a sounding-board!
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