Telegram has enabled voice calling for users in South Africa, after launching the feature in Europe on 30 March.
Calls are encrypted using a system that was built on the encryption Telegram uses for Secret Chats.
However, Telegram said it had to simplify and improve the key exchange mechanism for calling.
Instead of lengthy codes or complicated pictures to ensure that no one else is listening, Telegram callers compare a series of emoji that appear when a call is connected.
Where possible, calls will connect directly over a peer-to-peer connection. If that is not available, Telegram will use the closest available server.
“In the coming months, we’ll be expanding our content delivery network around the globe, getting the connection up to lightspeed even in remote areas,” said Telegram.
Telegram’s calling system also uses a neural network to learn from feedback, taking connection speed, latency, and packet loss data into account to improve the quality of calls.
Privacy settings for Telegram voice calling lets you specify who may call you, or switch off the feature.
Telegram calling tested
We tested Telegram voice with a device connected to fibre over Wi-Fi in South Africa and called a contact in Turkey.
Call quality was excellent, with no delay on either end.
When you call someone who has yet to update their app, or who is in a region that does not support the feature, you receive an error message.
The message states the call “failed to connect”, as shown below.