7.1

7.1 General characteristics

This feature allows the users to communicate by means of user-to-user signalling without setting up a circuit-switched connection. A temporary signalling connection is established and cleared in a manner similar to the control of a circuit-switched connection.

Table 6-6/Q.931

Mapping of X.25 cause to Q.931 cause
for premature clearing of the incoming call

	X.25 cause in clear indication packet				Q.931 error condition
Item	X.25/X.96 cause	Code	Diagnostic	Code	Q.931 cause	Code	Diagnostic
1	DTE originated	00	No additional information	0	Normal call clearing	016	(None)
1	DTE originated	1XX	DTE specified	XX	Normal call clearing	016	(None)
2	Network congestion	05	No additional information	0	Switchting equipment congestion	042	(None)
3	Out of order	09	No additional information	0	Destination out of order	027	(None)
4	Remote procedure error	17	(Any allowed)		Protocol error, unspecified	111	(None)
Note - Instead of providing the above mapping of X.25 to Q.931, the PH, as a network option, may code the Q.931 Cause information element to indicate CCITT Coding Standard in octet 3, X.25 in octet 3a, and code octets 4 and 5 according to Recommendation X.25, copying the cause from the X.25 clear indication packet rather than mapping it to a Q.931 cause.