54113
This service involves installing a special telephone interface at the customer 's premises that converts the analog signals from the customer 's in-home wiring into a digital signal , which is then sent on the local loop ( replacing the analog last mile , or plain old telephone service ( POTS ) ) to the company 's switching center , where it is connected to the public switched telephone network ( PSTN ) .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None