Call state
The purpose of the Call state information element is to describe the current status of a call, (see 2.1) or an access-connection (see 2.2) or a global interface state (see 2.4). The length of this information element is three octets. 8 7 6 5 4 3 2 1 1 0 0 0 1 0 1 0 0 - Information element identifier 2 - Length of call state contents 3 b b a a a a a a b) Coding standard (octet 3) Bits 8 7 0 0 CCITT standardized coding, as described below 0 1 ISO/IEC standard (Note) 1 0 National standard (Note) 1 1 Standard defined for the network (either public or private) present on the network side of the interface (Note) NOTE - These other coding standards should only be used only when the desired call states cannot be represented by CCITT-standardized coding. a) Call state value (octet 3) Bits 6 5 4 3 2 1 User State Network state 0 0 0 0 0 0 U0 - Null N0 - Null 0 0 0 0 0 1 U1 - Call initiated N1 - Call initiated 0 0 0 0 1 0 U2 - Overlap sending N2 - Overlap sending 0 0 0 0 1 1 U3 - Outgoing call proceeding N3 - Outgoing call proceeding U4 – Call delivered N4 – Call delivered U6 – Call present N6 – Call present U7 – Call received N7 – Call received U8 – Connect request N8 – Connect request U9 – Incoming call proceeding N9 – Incoming call proceeding U10 – Active N10 – Active U11 – Disconnect request N11 – Disconnect request U12 – Disconnect indication N12 – Disconnect indication U15 – Suspend request N15 – Suspend request U17 – Resume request N17 – Resume request U19 – Release request N19 – Release request – - - - - - N22 – Call abort U25 – Overlap receiving N25 – Overlap receiving Global interface state value (octet 3) Bits 6 5 4 3 2 1 State REST0 – Null REST1 – Restart request REST2 – Restart All other values are reserved.