1. The recording engineer dialled the operator. Could have been pulse dialling, could have been DTMF, doesn't matter.
2. Operator answered and the engineer said "I'd like to call London, collect, number 01xxx831".
3. Operator entered 044 1 xxx 831, and this was transmitted to another exchange in SS5 tones.
I didn't grow up in the USA, but a couple of people who did have said that, yes, they think that at least some of the time, you could hear the SS5 tones and also the initial conversation between the operator and whoever answered the phone. It may be that it depended on the operator, since they probably had a mute button, and maybe on the particular exchange the operator was in.
I think what happened is
1. The recording engineer dialled the operator. Could have been pulse dialling, could have been DTMF, doesn't matter.
2. Operator answered and the engineer said "I'd like to call London, collect, number 01xxx831".
3. Operator entered 044 1 xxx 831, and this was transmitted to another exchange in SS5 tones.
I didn't grow up in the USA, but a couple of people who did have said that, yes, they think that at least some of the time, you could hear the SS5 tones and also the initial conversation between the operator and whoever answered the phone. It may be that it depended on the operator, since they probably had a mute button, and maybe on the particular exchange the operator was in.
In the film, we hear from 3 onwards.