Here-doc literal @ (at symbol)

So, you have a here-doc/heredoc and need a literal @ at symbol for things like email addresses.
Answer: Replace it with \100.

3CXPhone dial from web page

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\dial]
@="URL:Dial Protocol"
"EditFlags"="hex:02,00,00,00"
"URL Protocol"=""

[HKEY_CLASSES_ROOT\dial\DefaultIcon]
@="C:\\Program Files (x86)\\Microsoft Lync\\Communicator.exe,0"

[HKEY_CLASSES_ROOT\dial\shell]

[HKEY_CLASSES_ROOT\dial\shell\open]

[HKEY_CLASSES_ROOT\dial\shell\open\command]
@="\"c:\\Program Files (x86)\\3CXPhone\\3CXPhone.exe\" %1"

So, copy that, put it in a .reg file, import it.
(NOTE THIS MODIFIES YOUR REGISTRY) Determine if you want to do this.
Now, if you have a link that says:
<a href="dial:8005551212">8005551212</a>

3cxPhone will dial that link.
8005551212