Complex sentence: The Eritrea Telecommunication Services Corporation, more commonly known as EriTel, is the sole operator of both landline and mobile telephone communication infrastructure in Eritrea, but is one of several internet service providers in the country.
Split into simpler sentences: The Eritrea Telecommunication Services Corporation, more commonly known as "EriTel" is the sole operator of both landline and mobile telephone communication infrastructure in Eritrea. However, it is one of several internet service providers in the country.