All channel numbers with a D suffix indicate a repeater output frequency used in simplex mode (for example, LLAW1D is simplex on the output frequency of LLAW1).Please refer to the wiki article for notes regarding the use of CTCSS tones on Low Band, VHF, UHF, and 800 Public Safety Common frequencies.nteroperability. VTAC17/17D are the same as Marine Channel 25 and may only be used in areas at least 100 miles from a navigable waterway, and by ground stations only (no aircraft use permitted).
Port Numbers in URLs. Port numbers can also be specified using URL. For example port 80 is by default for HTTP. when you type a dot com in your browser the browser sends request in the form of http://www.domain.com:80/ to the server which responds and transfers data.
The most commonly blocked ports are port 80 and port 25. Port 80 is the default port for http traffic. With blocked port 80 you will need to run your web server on a non-standard port. Port 25 is the default port for sending and receiving mail. ISPs block this port to reduce the amount of spam generated by worms on infected machines within their network.