This is a subscription time option, subscription to fast select requires extended
format to work.
This allows a mode of working similar to a datagram network. This is done
by carrying upto 128 bytes of data in the CALL, CALL CONNECTED and CLEAR packets,
an option is available to convert this into a normal call.
restricted response - clear only
unrestricted response - clear or call accept (extended format)
formats:
| 01 00 | no reverse charging or fast select |
| 01 01 | reverse charging |
| 01 C0 | fast select - restricted response |
| 01 80 | fast select - unrestricted response |
| 01 C1 | reverse charging and fast select - restricted response |
| 01 81 | reverse charging and fast select - unrestricted response |
