Communicating around the content

August 15, 2021

It was 2007 and text messaging was in the vogue, at least where I lived. Not sending messages over instant messaging apps such as Signal or WhatsApp, but Short Message Service (SMS). This was the time when I had one of my earliest mobile phones. It did not have internet connectivity. SMS and calling were its main functions.

Sending and receiving SMSes was a habit. Some days a few tens of messages and on other days a little more than hundred messages. SMSes were not free. We were able to pay a small lump-sum to have the privilege to send a few thousand SMSes over a month.

As useful as text messages were, there were times when we had to call each other. Calls were much more expensive. For someone still in school, with no income, saving costs was the priority. So we had to figure out a way to use the calling function of our mobile phones without having to pay for them. This was possible, as long as we did not need to speak over the phone. You might wonder, what might be the use of calling without speaking. Read on.

Lets say I was to travel to a book exhibition by train with my friend Sam. Sam lives a few kilometres away from my place and we board the train at different train stations. Sam boards the train at station A and I board the train at station B. Sam wants to make sure that we board the same train so that we can have a pleasant chat during the journey. We had decided that we will board the first carriage of the train in the direction of travel. We still needed a way to make sure we do not board different trains, especially as there was one train every 5 minutes on that particular route.

As Sam boarded the train before me, we decided that Sam will give me a “missed call” when he boards the train. A missed call is an intended termination of a call before the recipient answers it. I might miss an SMS without noticing it and we wanted to save costs by not speaking when he called. The missed call was a good solution for us.

We had recognized that we can communicate more than one message through missed calls. That is, the utility of missed calls went beyond 1-bit messages. We added another variable. The length of the ring before the call was terminated. When Sam boarded the train, he would give me a missed call that was terminated after the first ring. This missed call was sufficient for me to decide when to leave home. However, it was possible that I might walk slower than expected or might have to wait to buy train tickets. This meant that another nudge from Sam about the location of the train before it arrives at station B would help me.

Sam would give me another missed call. When the train had left the station preceding station B. This time he terminated the call after two rings. The second call was to alert me that the train was nearing station A and that I should rush had I not already arrived at the platform.

As proud as we were of our “free” communication, we soon learnt that our approach was not unique. If you check the Wikipedia page for missed call, you will notice that missed calls are used for marketing and political campaigns as well.

If the content of a call is what is spoken during the call, then a missed call does not have content. Nevertheless, the missed call can be used as a form of a private language1 specific to the individuals who are interacting and to the context in which they interact. I would not recommend this method for highly confidential messages as this is a form of security through obscurity.

What is also interesting to me is that missed calls maybe specific to mobile phones (and telephones in general), but the phenomenon of communicating without having to access the content of the medium is not new.

Imagine that you lived at a time when the receiver of letters paid for postage rather than the sender. In today’s world, where snail mail is not the quickest mode of communication, imagining such a world may not be easy. It might also be hard to imagine that you as the receiver have to pay for letters when the letter is delivered to you2. Doesn’t the sender pay for the postage?

Not if you lived in a world before 1840. Back then, the receiver had to pay for the postage. As in the case of calls, there are times when it is not necessary to read the contents of the letter before recognizing what the message is. This is possible as long as both sides have a pre-arranged method.

Letters are usually addressed to the recipient. The name and the address of the recipient is visible without opening the envelop. What can we learn from this? As a sender, you can communicate one message by writing the receiver’s full name and a different message by shortening the first name to an initial. When the receiver looks at the envelope, they can understand the message by the name the sender has written, without having to pay for postage and without reading any further3.

It is of course possible to create multiple variations. In today’s world, you can communicate messages by either typing the name of the recipient or by writing it using a pen. Or you can include the sender’s information on the right side of the envelop or on the left, preferably on the back. We would not communicate this way for the simple reason that the incentives have changed since 1840. The sender pays for the postage and they might as well write down their message in detail when they are paying for it.

These are two examples of how metadata is used to communicate. These are examples where the communicating parties intentionally use metadata to communicate. How often do we use metadata these days? How often do we use it intentionally to pass on a message? The answer is yes and no. Metadata is everywhere these days, but their use is not controlled by the sender or the receiver.

  1. I am not using the term “private language” in the philosophical sense of a language that is only understood by an individual, but rather as a language that is understood by only those, one or more, who understand the code.↩︎

  2. I am overlooking postage covered by return envelopes as the receiver pays in advance and not when they receive the letter.↩︎