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Vintage Telephony

VOIP Ready GPO 746 - Two Tone green

£97.00 Sold out

This telephone is fitted with our inDAT Pulse to Tone converter to give you tone dialling and, if you require, 'Star', 'Hash', 'Last Number Redial' and up to seven stored numbers. These options are switchable so the telephone can quickly be customised to your needs.

A classic British 746 series telephone re-cased in two-tone green, in first class working order and ready to plug in and use. Of course it has the quintessential twin bell 'ring ring', a No.21 dial and 21a transmitter unit for high quality speech. It also comes complete with our own reproduction paper furniture on which we can print your exchange and telephone number.


About the inDAT Full Feature Pulse to Tone Converter
This is another ‘Vintage Telephony’ product which we have produced because we were not happy with the quality of other products on the market.

Developed with Geoff Peters, the inDAT is an internal pulse to tone converter designed to function on VOIP lines (BT Digital Voice, Sky etc) and is near silent in operation.

Because we know a lot of our customers like vintage telephones to be kept as original as possible, our inDAT can operate in one of three modes.

1) Pulse to tone conversion only – dialling 0-9.
2) Pulse to tone conversion, 'Star' & 'Hash'.
3) Pulse to tone conversion, 'Star & Hash', 'Last Number Redial' & Stored Numbers.

Our inDAT is fitted internally. It is a single unit and requires no addition components.


Technical Notes
The inDAT has full bridge rectification to protect against reverse line polarity. It needs 24mA to operate which is matched or exceeded by all common VOIP services.

It has a balancing circuit to work with most types of microphone - carbon or electronic.

Once a dialled digit has been detected, the circuit will send out a corresponding tone burst to line using DTMF4 encoding. To solve the noise issue we have a muting device to attenuate the tone to an almost inaudible level.

Because of the current draw, the inDAT cannot be used in a circuit that has a Dial-A-Tone before it in the circuit. Rearranging the order of connection will resolve the issue.

Note: Because of variance across the new VOIP market, we supply all inDAT installations with a BT to BT ring capacitor adaptor. This will allow telephones to ring in VOIP connections that do not have a ring capacitor, but should not be used unless required. Please contact us and we will explain – it’s very straightforward!