Revision as of 22:21, 31 January 2012 by Beichner
Includes postal services and voice mail.
- Postal services - the services used to transmit physical objects and tangible letters across space
- Voice mail - a computer based system that allows users to exchange voice messages
This category has only the following subcategory.
Pages in category "Message systems"
The following 4 pages are in this category, out of 4 total.