look .. there is nothing like communication standards as one pool where u find all what u want about communications ..
Communications is either Theory or Systems ... you need first to read about theory .. then go for Systems ..
Communication Systems have thousands of standards .. better divide communication systems into sub domains .. like wired-communication .. wireless-communication .. or by field .. like Data Networks ( wired/wireless ) .. Cellular Communications .. many things ..
What is your country and area of interest? The most used is ITU (former CCITT) For Europe try ETSI (www.etsi.org). For USA Bellcore - Telcordia. Also for specific topics there are study groups and specialized forums (eg. ADSL )