Regarding North Korea’s telephone situation, Lankov, a North Korean researcher, can be helpful.
According to recent estimates, there are about 5.2 lines per 100 people. This figure includes the overwhelming majority of office phones. Of all telephone calls, only 20 percent are located in ordinary households.
Until the mid-1990s, Pyongyang was the only automatic telephone exchange. Automated switching has been introduced in major cities over the past decade, but in smaller towns and regions, connections are made through telephone operators.
Payphones were finally introduced in the 1980s. It is located in only a few major cities. The number is very small.
Thus, when it becomes necessary to make an emergency local call, North Koreans go to a post office with telephone service. (Andrey Lankov, North of the DMZ: Essays on Daily Life in North Korea)
Park Yong-mi, a defector from Hesan located in northern North Korea, testified as follows:
In Hesan, homes with telephones are still unusual, and mobile phones were only available to a handful of the wealthy. The only way to invite a girl who likes a boy to a date was to call him directly (Park Yong-mi, “The Choice to Live”)
He also explains that while Yong-mi Park talked to his father over the phone, the call was intercepted by police.
“Dad is alright, Young-mi,” said the father. “I’m really happy to hear you. Where are you now?” Police intercept illegal calls, so I can’t talk for long. (Ibid.)