Definition: portable

1. During a meal

Never leave your phone switched on on the table: this is an affront to your fellow diners. The most polite thing to do is to switch it off conspicuously before the meal. You can even accompany the gesture with the words "I'm switching off my phone": this is a sign of consideration. If you are expecting a really important call, it is best to let those around you know. When the phone rings, say "excuse me" and turn away before answering. Better still, stand up and keep the phone conversation as brief as possible. When you return to the table, say "excuse me". This is the minimum you should do.

2. The ringtone

When selecting a ringtone for your mobile phone, avoid at all costs choosing electronic versions of classical hits (RTL selection) such as Bach's Toccata, the overture to William Tell and other Carmen pieces. This is an insult to the great composers. The height of vulgarity is reached with the music from the film "Titanic" in the "Bontempi organ" version remixed by Motorola.

3. Face to face

Your phone rings while you are talking face to face with someone. Politeness dictates that you reject the call, but this is not always possible. If there is really no other solution, then apologise, turn away and answer the call, suggesting that you will call back a little later. If the phone call is taking a long time, avoid looking at the person who is waiting. Nothing is more humiliating than being faced with someone who is watching you while you talk to someone else.

4. The line goes dead

When using your mobile phone, always try to warn the other person about a possible loss of signal: "I'm on the train, if I get cut off I'll call you back later." After an unexpected interruption, call back, even if it is much later, and apologise.

5. Leaving the cinema

The film is over, dozens of viewers leave the theatre and quickly turn their mobile phones back on. Don't do as they do: they look ridiculous. They demonstrate their submission to the network, their dependence on their phones and a certain contempt for their companions. Out of courtesy to the person who accompanied you to the cinema, refrain from turning on your mobile phone when leaving the theatre, or do so discreetly.

6. On public transport

You are sitting alone on a bus or train. Your phone rings. You can answer it, but please don't talk too loudly. If you find yourself sitting opposite someone who is shouting into their mobile phone, show them that you are listening and nod at the end of their sentences: you'll see, they'll eventually lower their voice.

7. While walking

Never forget that your voice sounds breathless when you talk on the phone while walking. The person you are talking to will think you are upset, sobbing or on the verge of a nervous breakdown. Tell them you are walking to avoid any misunderstandings.

8. "The mobile subscriber cannot be reached"

Never, ever criticise someone for turning off their phone. It is their absolute right. Leave a message on their voicemail and ask them to call you back if necessary, but avoid messages such as "What are you doing? I've been trying to reach you all day." It's rude.

9. The earpiece

Earpieces, which are very popular with businesspeople, should be discreet and elegant. The height of bad taste, as observed at Telecom, is to leave the wire hanging down from your ear all the time.

10. "Where are you?"

Inevitable when calling a friend on their mobile: the introductory "Where are you?". Opt for the more polite "Am I disturbing you?", which will often elicit the same response: "No, I'm on the train/bus/at the airport/in the queue to buy tickets". It's more polite. Because if they don't want to reveal their location, the person on the other end can at least choose not to answer.