were used for the first time to distribute communications during and after disasters. American entry-level Novice and Technician class licensees were granted CW and SSB segments on the 10 Meter Band in 1987. The frequency ranges allocated to them are still known today throughout much of the world as the Novice Sub Bands even though it is no longer possible to obtain a Novice class license in the US. Further advances in digital communications occurred in the 1990s as Amateurs used the power of PCs and sound cards to introduce such modes as PSK31 and began to incorporate digital signal processing and software-defined radio into their activities. 21st century For many years, amateur radio operators were required by international agreement to demonstrate Morse code proficiency in order to use frequencies below 30 MHz. In 2003 the World radiocommunications conference (WRC) met in Geneva, Switzerland, and voted to allow member countries of the International Telecommunication Union to eliminate Morse code testing if they so wished . On December 15, 2006, the United States Federal Communications Commission (FCC) issued a Report and Order eliminating all Morse code testing requirements for all American Amateur Radio License applicants, which took effect February 23, 2007. The relaxing of Morse code tests has also occurred in most other countries, resulting in a boosting in the number of radio amateurs worldwide. While there is no longer a requirement for hams to learn "the Code", it remains a popular communications mode. Most of Europe allows licensed operators from other countries to obtain permits to transmit in Europe during visits. Residential permits are available in many countries globally whereby a valid license from one country will be honored by other countries under international treaties. In early 2010, only North Korea had an absolute ban on ham radio operator licenses, although many countries still maintain careful records of ham licensees, and limit their activities and frequency bands and transmit power output. Amateur radio emergency communications assisted in disaster relief activities for events such as the September 11 attacks in 2001, Hurricane Katrina in 2005, and the Sichuan earthquake in 2008. In 2017, the Red Cross requested 50 amateur radio operators be dispatched to Puerto Rico to provide communications services in the wake of Hurricane Maria. See also Amateur radio licensing in the United States - Contains history of U.S. amateur licensing by the Department of Commerce, the Federal Radio Commission