Telecommunication = Tele + Communication, i.e. communication at a distance. Tele is Greek and is a common prefix in English for "distant".
Communication is a how information is exchanged, it's a process event or occurrence. Communication can take many forms such as
- telegraphy, pretty old terms they are telex, telegram, facsimile etc. Optical telegraphs could be smoke signals or beacons. Electrical telegraph could be Morse code
- telephone, of course these days this could be fixed line or mobile
- computer network