[aprssig] What is "TNC Channel Switching"?

[Andrew Pavlin]

Greetings, all.

I was slogging through the APRS spec, and came upon a mention that the ASCII characters '|' and '~' were reserved for TNC channel switching, and couldn't appear in any messages or even as a symbol code.

What does this mean, and is it still applicable? Will I break the APRS-IS or some ancient TNC somewhere if I send those characters in an APRS message?

Just curious.

Andrew Pavlin, KA2DDO
Sent from my Verizon Wireless BlackBerry