Thank you, Vietnam Telecom, for reminding us of the complexity that lies at the heart of all telephonic communication. We forget that this is the logical form of the system, even when we’re using mobile phones.

Vietnam’s fixed-line subscribers number between 15 and 17 million and they are served by a spider’s web of cables bundled together and hung on hugely over-burdened street-side pylons. The weight of them must amount to thousands of tons. When a line is broken, it is easier to lay a new one than to find the broken one.

There are more than 120 million mobile subscribers, nearly ten times as many as landline subscribers, supported by a virtually invisible network that weighs nothing at all.

What’s the point of landlines?