Context: For customers with more demanding requirements (such as medium-to-large businesses, or other ISPs) can use higher-speed DSL (such as single-pair high-speed digital subscriber line), Ethernet, metropolitan Ethernet, gigabit Ethernet, Frame Relay, ISDN Primary Rate Interface, ATM (Asynchronous Transfer Mode) and synchronous optical networking (SONET).

Question: What type of customers would typically have more demanding requirements? 
Answer: medium-to-large businesses, or other ISPs

Question: what does atm stand for in relation to internet providers? 
Answer: Asynchronous Transfer Mode

Question: what is high-speed dsl used for? 
Answer: customers with more demanding requirements

Question: what is SONET? 
Answer: synchronous optical networking

Question: What is available to customers with less demanding requirements?
Answer: Unanswerable

Question: What's the abbreviation for synchronous transfer mode
Answer: Unanswerable

Question: What are the abbreviations for asynchronous optical networking
Answer: Unanswerable