Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Digital Subscriber System No. 1
open-in-new
<h2 id="references">References</h2> <ol> <li id="fn:1"><p>Integrated Services Digital Network (ISDN); User-network interface layer 3 Specifications for basic call control <a href="http://www.etsi.org/deliver/etsi_i_ets/300100_300199/30010201/01_60/ets_30010201e01p.pdf" target="_blank">http://www.etsi.org/deliver/etsi_i_ets/300100_300199/30010201/01_60/ets_30010201e01p.pdf</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> </ol>