The Conversation – focussing on technology by James Balderson

The sight of the first makes it like someone with a sniper rifle. We get the impression this is more than just surveillance with a so-called rifle microphone. We see through the sights he is using, in a manner reminiscent of films like Day of the Jackal (1973, directed by Fred Zinnemann).

There is a strange noise all through this scene, signifying the microphone noise which will later be filtered out by Caul.

From the soundtrack we are aware that a second mic is associated with a man with a beige earphone, like a body guard or secret service person. He's following the couple about – we don't see the mic at first.

We are led into the surveillance van which looks like a amateur recording with the three UHER Report 4000 IC tape decks recording the three microphones.

Now we see the third mic – a parabolic – which is picking up the most noise. We get the impression that these are home made.

We see the second microphone now, inside a gift inside a shopping bag. This microphone is the smallest of the three. The bag is a bit too ripped to pass as a new shopping bag just bought. The package contains a microphone, a battery, a tape recorder and a transmitter.

The people inside the van look like early agents. In modern films we see vans and even articulated lorries (“Next”, 2007 Directed by Lee Tamahori) walled with high-tech equipment, here there just seem to be tape loops, headphones and that's about it. It all feels very amateurish and home grown – very “” ( TV, 2006,7) in fact.

We then learn how all these microphones are being connected into a system providing coverage of the whole plaza, each contributing different and overlapping portions of the (40% coverage for the rifle mic, 80% for the shopping bag, 20% for the parabolic).

In Caul's home we see only a telephone (which we learn he never gives out the number to) and a mono Grundig Hi-Fi, which he plays his sax along to. This is where he unwinds, confident he will not be disturbed.

In Caul's office we find a treasure chest of technology, most of which he has built himself or assembled as this equipment was new and not available together. The reel-to-reels are from recording studios, the mixer from the film industry. The Ampex354 is the thing its all being mixed to – at the time a fledgling data storage technology. (Ampex now store security data in the US for big corporations and government). The lab looks very hi-tech for the time.

His assistant – Stan – makes and repairs equipment. In contrast he looks like a car mechanic where Caul looks like an FBI agent: nondescript.

Caul and Stan have made a sound filter to up the conversation between the couple. This sound filter looks very home made.

Caul spies on the couple when they get a room, using a very professional looking piece of equipment.

It transpires Caul himself is being bugged, and I believe that it is being done using his friend's phone-bugging technique, although despite all his knowledge of surveillance he is unable to find the bug.