Complex sentence: The People in Need Trust is a charity in the Republic of Ireland which has as its main fundraiser a Telethon, known as the RTÉ People in Need Telethon, which has been broadcasted by RTÉ since 1988, and supported by Eircom (formerly Telecom Eireann).
Split into simpler sentences: The People in Need Trust is a charity in the Republic of Ireland. It has its main fundraiser the RTÉ People in Need Telethon, which has been broadcasted by RTÉ since 1988, and supported by Eircom (formerly Telecom Eireann).