Year 48 (XLVIII) was a leap year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Vitellius and Poplicola (or, less frequently, year 801 Ab urbe condita). The denomination 48 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Classless Inter-Domain Routing (CIDR, or ) is a method for allocating IP addresses and routing Internet Protocol packets. The Internet Engineering Task Force introduced CIDR in 1993 to replace the previous addressing architecture of classful network design in the Internet. Its goal was to slow the growth of routing tables on routers across the Internet, and to help slow the rapid exhaustion of IPv4 addresses.

Polish telephone numbers have since 30 September 2009 (per Directive of the Minister of Infrastructure dated 28.01.2008 (Dziennik Ustaw, 2008, no. 52, pt. 307)) 9 digits.