relays, dial speed impulse tester

Hi I am in to vintage telephones {sort of}and I have a n043 dial speed impulse tester I wanted to get going ,but I do not know how and what components to use ,I have a little bit of information that was written in another forum and it went like this I have one I use all the time. They step when connected, rather than when disconnected, and a dial disconnects. (hope that makes sense). They'd have been used with an impulse accepting relay at the exchange. The coil of the tester I believe is 350 ohm, I use mine on 36v from an HP printer PSU (check car boot sales etc). The psu has a +24v and -12v supply, which seems to operate it fine. The relay is fairly non-critical, as you have no line length to distort the impulses, but 1-200 ohms would provide the limiting needed to run the phone, mine uses a 300 Ohm relay coil. As a power supply, you could probably use 3 or 4 pp3 batteries in series, as the current consumption is pretty low when not directly pulsing. I've attached a diagram (hopefully) that I knocked up quickly. It's important when running on batteries to include an on/off switch, as with no phone connected, the coil of the tester is energized. (It energizes during breaks in the line current) One final tip, don't try to reset the lever of the 43 tester when it's energized (IE if the phone's off hook or disconnected), it'll fight back! (done that a few times!) Now I do have the tester the power supply and dial but what relays does it need please and anybody know where to get them

the 240v ac is wrong it is obviously 24 to 36 vdc sorry about that