SIST EN 300 324-1 V1.2.3:2005

• Abstract:

  Request for a new edition of the V5.1 interface specification (part 1) to incorporate/include the amendments A1 and the changes in the PSTN restart procedures by leaving the DiSCONNECT COMPLETE message as it is and not send DISCONNECT COMPLETE in state AN1 or LE1 and treat the message as an unexpected message in the OUT OF SERVICE state. The aim is also to include further comments discussed during the time frame not later than milestone 6 for this work item.

• Status: Published
• Publication Date: 31-Mar-2005
• ICS: 33.040.30 - Switching and signalling systems
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Apr-2005
• Due Date: 01-Apr-2005
• Completion Date: 01-Apr-2005
• Ref Project: ETSI EN 300 324-1 V1.2.2 (1999-06) - V interfaces at the digital Local Exchange (LE); V5.1 interface for the support of Access Network (AN); Part 1: V5.1 interface specification

SIST EN 300 324-1 V1.2.3:2005 is the Slovenian adoption of EN 300 324-1 Version 1.2.3 from ETSI. It specifies the electrical, physical, procedural and protocol requirements for the V5.1 interface between an Access Network (AN) and a Local Exchange (LE), for analogue telephone access, ISDN basic access, Permanent Line (PL) capability, semi-permanent leased lines and permanent leased line services.

What does SIST EN 300 324-1 V1.2.3:2005 specify?

SIST EN 300 324-1 V1.2.3:2005 specifies the V5.1 interface between an AN and an LE, including the physical layer, signalling procedures, protocol architecture, control, and provisioning rules. In practice, it is the reference for designing how access-network equipment and local-exchange equipment exchange bearer traffic, signalling, and management information.

The document is organized in a logical order: clauses 4 and 5 cover the interface at Layer 1, clauses 6 to 8 cover services and protocol architecture, clauses 9 to 12 cover the LAPV5 sublayers and frame relay, clauses 13 and 14 cover PSTN signalling and control, and the annexes provide management guidance, coding rules, examples and state-machine material.

Permanent lines that bypass the LE are outside the scope, while semi-permanent leased lines and PL capability on ISDN-BA are treated within the specification.

Annex	What it covers
Annex C	Basic requirements of the system management functions in AN and LE
Annex D	Use of protocol information elements for national PSTN protocols
Annex E	Service scenarios, architecture and functional definition of access arrangements with AN at the LE
Annex F	Concept and requirements for upgrade of a V5.1 interface to a V5.2 interface
Annex G	Use of function element primitives in the V5 PSTN protocol
Annex H	Explanatory notes and information flow for the PSTN protocol
Annex K	Layer 3 PSTN protocol error detection procedure
Annex L	SDL diagrams for AN and LE procedures
Annex N	Protocol architecture for ISDN and PSTN user port status control information transfer
Annex P	Items identified to be pre-defined or provisioned

What are the key requirements of SIST EN 300 324-1 V1.2.3:2005?

SIST EN 300 324-1 V1.2.3:2005 is built around a single 2 048 kbit/s V5.1 link, layered signalling, and clear separation between bearer traffic, port control, and management. The main practical message is that the interface is not just a transport path - it defines how traffic is framed, multiplexed, controlled, and recovered after errors.

Physical interface and Layer 1

Clause 4 states that the V5.1 interface uses a single 2 048 kbit/s interface and may use ETSI standard transmission systems designed for that signal rate. Clause 5 ties the functional and procedural behaviour to the 2 048 kbit/s case in ETS 300 167, including CRC-4 handling and CRC error reporting.

For implementers, this means the electrical and framing behaviour must match the selected transmission structure, not only the V5.1 signalling rules. Testing therefore has to cover line characteristics, framing, alignment and CRC behaviour together.

Services carried over V5.1

Clause 6 covers on-demand services, PL capability, semi-permanent leased lines and permanent leased line services. PSTN and ISDN Basic Access (ISDN-BA) are carried through the interface, while PL capability uses one or both B-channels of an ISDN-BA and bypasses the LE.

For users of the standard, the key distinction is whether traffic is switched through the LE or stays in the AN. That decision affects provisioning, signalling, and which parts of the protocol stack are active.

Time slots, C-channels and congestion control

Clause 8 defines how timeslots are allocated and how signalling is multiplexed. Timeslots 1 to 31 are assigned by provisioning for bearer channels, and control uses C-channels, with the control C-path always allocated to C-channel 1.

Clause 8.7 lists the congestion-control mechanisms: end-to-end flow control, congestion control on the V5.1 interface, blocking of ISDN user ports at L2, and flow control using LAPV5-DL mechanisms. In practice, network planners need to choose how traffic is limited or blocked when the interface is overloaded.

LAPV5-EF and LAPV5-DL behaviour

Clauses 9 and 10 split LAPV5 into the Envelope Function sublayer (LAPV5-EF) and the Data Link sublayer (LAPV5-DL). LAPV5-EF defines frame structure, addressing, transparency, FCS and invalid-frame handling, while LAPV5-DL defines the peer-to-peer data-link procedures, including multiple-frame acknowledged operation and link establishment and release.

The standard says LAPV5-DL peer-to-peer communication uses multiple-frame acknowledged information transfer only. That matters because the implementation has to support stateful link management, retransmission and recovery rather than a simple transparent link.

AN frame relay and sublayer communication

Clause 11 says the AN executes an AN frame relay function, which means the customer D-channel is not fully terminated in the AN. The AN delimits frames, preserves transparency, multiplexes and demultiplexes them by address, and discards invalid frames received from an ISDN user port without notifying the sender.

Clause 12 defines how frames move between LAPV5-EF, LAPV5-DL and AN-FR. The EFaddr and V5DLaddr values are used to route frames to the correct sublayer, so address handling is central to correct interworking.

PSTN signalling and error handling

Clause 13 specifies the PSTN signalling protocol. The main message set includes ESTABLISH, ESTABLISH ACK, SIGNAL, SIGNAL ACK, STATUS, STATUS ENQUIRY, DISCONNECT, DISCONNECT COMPLETE and PROTOCOL PARAMETER, with information elements for signalling, line information, sequence handling and related functions.

The error-handling rules are strict: received messages are checked in a defined order for protocol discriminator, L3addr, message type, information-element sequence, missing or repeated mandatory elements, unrecognized elements and unexpected messages. For operators and testers, this means malformed or out-of-context signalling is handled deterministically before any state change is allowed.

Clause 13 also defines timers, state maps and restart behaviour. The state machine tables in this clause are the basis for call setup, active call handling, disconnect and recovery.

Control, maintenance and re-provisioning

Clause 14 defines the control requirements as normative FSM specifications. It covers ISDN user port status indication and control, PSTN user port status indication and control, interface L1 maintenance, the control protocol, and V5.1 re-provisioning procedures.

The control protocol uses PORT CONTROL, PORT CONTROL ACK, COMMON CONTROL and COMMON CONTROL ACK messages, along with start traffic and stop traffic indications. In practice, this is the part of the standard that lets the AN and LE coordinate activation, deactivation, traffic enabling, maintenance and variant changes.

What terms does SIST EN 300 324-1 V1.2.3:2005 define?

• Access Network (AN) - the system between the LE and the user, replacing part or all of the local line distribution network.
• Local Exchange (LE) - the exchange where user lines are terminated via an AN.
• Permanent Line (PL) - a capability that uses one or both B-channels of an ISDN-BA and bypasses the LE.
• LAPV5-EF - the Envelope Function sublayer that carries peer-to-peer frames and associated addresses.
• LAPV5-DL - the Data Link sublayer that provides the acknowledged peer-to-peer data-link procedures.
• Envelope Function address (EFaddr) - the address in LAPV5-EF frames that identifies a V5 enveloping-function connection.
• V5 Data Link address (V5DLaddr) - the address in LAPV5-DL frames that identifies a V5 data-link sublayer connection.

Who uses SIST EN 300 324-1 V1.2.3:2005?

SIST EN 300 324-1 V1.2.3:2005 is used by equipment vendors, network operators, and engineers who implement or verify the AN-to-LE interface. It is relevant for access-network design, local-exchange integration, signalling interworking, and provisioning of PSTN, ISDN-BA and leased-line services.

It is also used by test and quality teams that need to validate physical-layer behaviour, frame formats, state-machine transitions, timer handling, and error recovery. Buyers and technical evaluators use it to check whether a product supports the required V5.1 functions and service mix.

What changed in SIST EN 300 324-1 V1.2.3:2005 from the previous edition?

The scope states that this new edition incorporates amendment A1 and updates the PSTN restart procedure. The stated change keeps DISCONNECT COMPLETE as it is, avoids sending DISCONNECT COMPLETE in state AN1 or LE1, and treats that message as unexpected in the OUT OF SERVICE state.

Which standards are used with SIST EN 300 324-1 V1.2.3:2005?

Reference	What it contributes
ETS 300 166	The physical interface reference for the 2 048 kbit/s link
ETS 300 167	Functional and procedural requirements for the 2 048 kbit/s case, including CRC-4 behaviour
ITU-T G.703	Electrical and optical characteristics and pulse-mask requirements for the interface
ETS 300 125	The LAPD basis used for LAPV5-DL procedures and state-transition tables
ETS 300 297	The line transmission system reference for the ISDN basic access case with NT1
ETS 300 403-1	The DSS1 network-layer signalling reference for circuit-mode basic call control
ETS 300 379-1 and ETS 300 379-2	Q3 management-interface references for fault and performance management
ETR 150	Mapping examples for the PSTN protocol

What does the SIST EN 300 324-1 V1.2.3:2005 document contain?

The document contains tables for message types, information-element coding, timers, state maps and port-control states. It also includes procedures for frame handling, link establishment, multiple-frame operation, error recovery, PSTN path control, restart, control messaging and re-provisioning.

Annex D gives the placement and coding of information elements for national PSTN protocols, while Annex K explains layer 3 error detection with examples. Annex L provides SDL diagrams for the AN and LE sides, and Annex G shows how function element primitives are used in the PSTN protocol.

Together, these sections give implementers the material needed for design, interoperability testing, troubleshooting and protocol conformance work without reproducing the original normative text.

SLOVENSKI STANDARD
01-april-2005
Vmesniki V pri digitalnih krajevnih centralah (LE) – Vmesnik V5.1 za podporo
dostopovnemu omrežju (AN) – 1. del: Specifikacija vmesnika V5.1
V interfaces at the digital Local Exchange (LE); V5.1 interface for the support of Access
Network (AN); Part 1: V5.1 interface specification
Ta slovenski standard je istoveten z: EN 300 324-1 Version 1.2.3
ICS:
33.040.30 Komutacijski in signalizacijski Switching and signalling
sistem systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 300 324-1 V1.2.3 (1999-06)
European Standard (Telecommunications series)
V interfaces at the digital Local Exchange (LE);
V5.1 interface for the support of Access Network (AN);
Part 1: V5.1 interface specification

2 ETSI EN 300 324-1 V1.2.3 (1999-06)
Reference
REN/SPS-09050-1 (30090iq0.PDF)
Keywords
V interface, V5 interface, LE, AN
ETSI
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All rights reserved.
ETSI
3 ETSI EN 300 324-1 V1.2.3 (1999-06)
Contents
Intellectual Property Rights.14
Foreword .14
Introduction .15
1 Scope.17
2 References.18
3 Definitions, symbols and abbreviations.19
3.1 Definitions . 19
3.2 Symbols and abbreviations . 21
4 Electrical and physical interface requirements .23
5 Procedural interface requirements .28
6 Services and architecture aspects and requirements .31
6.1 On-demand services. 31
6.1.1 PSTN. 31
6.1.2 ISDN Basic Access (ISDN-BA). 32
6.2 Permanent Line (PL) capability . 32
6.3 Semi-permanent leased line . 32
6.4 Permanent leased line services. 33
7 Control and provisioning .34
7.1 Control principles . 34
7.1.1 General requirements and assumptions . 34
7.1.2 Control of ISDN user port for the PL capability . 36
7.1.2.1 Statements and assumptions . 36
7.1.2.2 ISDN and PL capability. 36
7.1.2.3 Decoupling of AN and LE FSM . 36
7.2 Provisioning strategy and requirements . 36
7.2.1 General. 36
7.2.2 Provisioning requirements. 36
8 Protocol architecture and multiplexing structure.38
8.1 Functional description. 38
8.2 Protocol requirements for PSTN and ISDN. 39
8.3 Time slots. 40
8.4 Time slot allocation for C-channels . 40
8.5 L2 sublayering and multiplexing on C-channels. 41
8.6 L3 multiplexing. 41
8.7 Congestion control. 41
8.7.1 Flow control end to end. 41
8.7.2 Congestion control on the V5.1 interface. 41
8.7.3 Blocking of ISDN user ports at L2. 41
8.7.4 Flow control using LAPV5-DL mechanisms. 42
9 Envelope Function sublayer of LAPV5 (LAPV5-EF).42
9.1 Frame structure for peer-to-peer communication. 42
9.1.1 General. 42
9.1.2 Flag sequence. 42
9.1.3 Interframe time fill . 42
9.1.4 Envelope function address field . 42
9.1.5 Envelope information field. 43
9.1.6 Transparency. 43
9.1.7 FCS . 43
9.1.8 Format convention. 43
9.1.9 Invalid frames. 43
ETSI
4 ETSI EN 300 324-1 V1.2.3 (1999-06)
9.1.10 Frame aborts. 43
9.2 Format of fields for data link envelope peer-to-peer communication . 44
9.2.1 Envelope function address field format. 44
9.2.2 Address field variables. 44
9.2.2.1 Address field extension bit . 44
9.2.2.2 EFaddr . 44
10 Data link sublayer of LAPV5 (LAPV5-DL).44
10.1 Frame structure for peer-to-peer communication. 44
10.1.1 General. 44
10.1.2 Link address field. 45
10.1.3 Control field . 45
10.1.4 Information field . 45
10.1.5 Format convention. 45
10.2 Invalid frames . 45
10.3 Elements of procedures and formats of fields for data link sublayer peer-to-peer communication. 45
10.3.1 Link address field format . 45
10.3.2 Link address field variables. 45
10.3.2.1 Address field extension (EA) bit . 45
10.3.2.2 Command/response field bit . 45
10.3.2.3 V5DLaddr. 46
10.3.3 Control field formats . 46
10.3.4 Control field parameters and associated state variables . 46
10.3.5 Frame types . 46
10.4 Definition of the peer-to-peer procedures of the data link sublayer. 46
10.4.1 General. 46
10.4.2 Procedure for the use of the Poll/Final (P/F) bit. 48
10.4.3 Terminal Endpoint Identifier (TEI) management procedures . 48
10.4.4 Automatic negotiation of data link layer parameters. 48
10.4.5 Procedures for establishment and release of multiple frame operation .48
10.4.5.1 Establishment of multiple frame operation . 48
10.4.5.1.1 General. 48
10.4.5.1.2 Establishment procedures. 49
10.4.5.1.3 Procedure on expiry of timer T200 . 49
10.4.5.2 Information transfer. 50
10.4.5.3 Termination of multiple frame operation. 50
10.4.5.4 Link-not-established state . 50
10.4.5.5 Collision of unnumbered commands and responses . 50
10.4.5.5.1 Identical transmitted and received commands. 50
10.4.5.5.2 Different transmitted and received commands. 50
10.4.5.6 Unsolicited DM response and SABME command. 50
10.4.6 Procedures for information transfer in multiple frame operation . 51
10.4.7 Re-establishment of multiple frame operation. 51
10.4.7.1 Criteria for re-establishment . 51
10.4.7.2 Procedures . 51
10.4.8 Exception condition reporting and recovery . 51
10.4.9 List of system parameters. 52
10.4.10 Data link monitor function . 52
10.4.10.1 General . 52
10.4.10.2 Data link layer supervision in the multiple-frame-established state. 52
10.4.10.3 Connection verification procedures . 52
10.4.11 PSTN and control data link FSM and requirements. 52
10.4.11.1 General . 52
10.4.11.2 Data link FSM . 53
11 AN frame relay sublayer .55
11.1 General. 55
11.2 Invalid frames . 55
11.3 Detailed description of the AN frame relay function . 56
11.3.1 Frame received from LE. 56
11.3.2 Frame received from ISDN user port . 56
ETSI
5 ETSI EN 300 324-1 V1.2.3 (1999-06)
12 Sublayer-to-sublayer communication and MF.57
12.1 LAPV5-EF to LAPV5-DL communication. 57
12.2 LAPV5-DL to LAPV5-EF communication. 57
12.3 AN-FR to LAPV5-EF communication. 57
12.4 LAPV5-EF to AN-FR communication. 57
13 PSTN signalling protocol specification and L3 multiplexing.57
13.1 General. 57
13.1.1 Introduction. 57
13.1.2 Separation of responsibilities . 58
13.1.3 National specific PSTN signal information elements. 58
13.2 PSTN protocol entity definition. 59
13.2.1 Definition of PSTN path states and explanation. 59
13.2.1.1 Path states in the AN (AN(PSTN)). 59
13.2.1.2 Path states in the LE (LE(PSTN)) . 59
13.2.2 Definition of PSTN protocol primitives, messages and timers. 60
13.3 PSTN protocol message definition and content . 61
13.3.1 Establish. 62
13.3.2 Establish ACK. 62
13.3.3 Signal . 63
13.3.4 Signal ACK . 63
13.3.5 Status. 63
13.3.6 Status enquiry. 64
13.3.7 Disconnect. 64
13.3.8 Disconnect complete . 64
13.3.9 Protocol parameter . 65
13.4 General message format and information element coding . 65
13.4.1 Overview. 65
13.4.2 Protocol discriminator. 66
13.4.3 L3addr. 66
13.4.4 Message type. 66
13.4.5 Coding of other information elements. 67
13.4.6 Single octet information elements . 68
13.4.6.1 Pulse notification . 68
13.4.6.2 Line-information. 68
13.4.6.3 State. 68
13.4.6.4 Autonomous-signalling-sequence . 69
13.4.6.5 Sequence-response. 69
13.4.7 Information elements with variable length format. 69
13.4.7.1 Sequence-number . 69
13.4.7.2 Cadenced-ringing. 70
13.4.7.3 Pulsed-signal. 71
13.4.7.4 Steady-signal . 72
13.4.7.5 Digit-signal . 73
13.4.7.6 Recognition-time . 74
13.4.7.7 Enable-autonomous-acknowledge . 74
13.4.7.8 Disable-autonomous-acknowledge . 75
13.4.7.9 Cause . 76
13.4.7.10 Resource-unavailable. 77
13.4.7.11 Enable-metering. 77
13.4.7.12 Metering-report. 78
13.4.7.13 Attenuation . 79
13.5 PSTN call control procedures. 79
13.5.1 General. 80
13.5.2 Handling of error conditions . 80
13.5.2.1 Protocol discriminator error. 81
13.5.2.2 L3addr error. 81
13.5.2.3 Message type error. 81
13.5.2.4 Information element out of sequence. 82
13.5.2.5 Repeated information elements. 82
13.5.2.6 Mandatory information element missing . 82
ETSI
6 ETSI EN 300 324-1 V1.2.3 (1999-06)
13.5.2.7 Unrecognized information element. 83
13.5.2.8 Content error of mandatory information element. 83
13.5.2.9 Content error of optional information element . 83
13.5.2.10 Unexpected message. 84
13.5.2.11 Optional information element not allowed . 84
13.5.2.12 Optional information element missing. 84
13.5.2.13 Status enquiry procedure . 84
13.5.2.14 Status procedure . 85
13.5.3 Path related procedures . 86
13.5.3.1 Path initiation by AN. 87
13.5.3.1.1 Subscriber seizure request. 87
13.5.3.1.2 Subscriber seizure confirmation. 87
13.5.3.2 Path initiation by LE. 88
13.5.3.2.1 Establish request . 88
13.5.3.2.2 Establish acknowledge. 89
13.5.3.3 Path collision . 89
13.5.3.3.1 Originating call prevail . 90
13.5.3.3.2 Destination call prevail . 90
13.5.3.4 Path active . 90
13.5.3.4.1 Normal operation . 90
13.5.3.4.2 Exceptional procedures. 91
13.5.3.5 Disconnecting path . 91
13.5.3.5.1 Disconnect request . 92
13.5.3.5.2 Disconnect acknowledge. 93
13.5.3.6 Line information procedure . 93
13.5.3.6.1 Normal operation . 93
13.5.3.6.2 Exceptional procedures. 94
13.5.4 Non-path related procedures . 94
13.5.4.1 Protocol parameter procedures . 94
13.5.4.1.1 Normal operation . 94
13.5.4.1.2 Exceptional procedures. 94
13.5.4.2 Port blocking procedures. 95
13.5.4.3 Restart procedure. 95
13.5.5 L3 error detection procedure. 96
13.5.5.1 Multiple SIGNAL message operation - variables, sequence numbers and timers . 96
13.5.5.1.1 Modulus . 96
13.5.5.1.2 Send sequence variable S(S) . 96
13.5.5.1.3 Acknowledge sequence variable S(A). 96
13.5.5.1.4 Send sequence number M(S) . 96
13.5.5.1.5 Receive sequence variable S(R). 96
13.5.5.1.6 Receive sequence number M(R) . 97
13.5.5.1.7 Timer Tt. 97
13.5.5.1.8 Timer Tr. 97
13.5.5.2 Multiple SIGNAL message operation - procedures. 97
13.5.5.2.1 Initialization . 97
13.5.5.2.2 Sending a SIGNAL message. 97
13.5.5.2.3 Sending a SIGNAL ACK message. 97
13.5.5.2.4 Receiving a SIGNAL message. 97
13.5.5.2.5 Receiving a SIGNAL ACK message. 97
13.5.5.2.6 Start of timer Tr . 98
13.5.5.2.7 Stop of timer Tr. 98
13.5.5.2.8 Timeout of timer Tr . 98
13.5.5.2.9 Start of timer Tt. 98
13.5.5.2.10 Stop of timer Tt. 98
13.5.5.2.11 Timeout of timer Tt. 98
13.5.5.2.12 Receiving a DISCONNECT message . 98
13.5.5.3 Multiple SIGNAL message operation - values . 98
13.5.5.3.1 Number of outstanding SIGNAL messages . 98
13.5.5.3.2 Timer Tt. 98
13.5.5.3.3 Timer Tr. 98
ETSI
7 ETSI EN 300 324-1 V1.2.3 (1999-06)
13.6 List of system parameters. 99
13.7 AN and LE side state tables . 99
14 Control requirements and protocol .105
14.1 ISDN user port status indication and control protocol. 105
14.1.1 General aspects. 105
14.1.2 Events and function elements relevant for the control of the state machines . 107
14.1.3 ISDN user port FSMs, AN (ISDN port) and LE (ISDN port). 109
14.1.3.1 Description of the states. 109
14.1.3.2 Definition of port control states. 110
14.1.3.2.1 ISDN user port FSM - AN (ISDN port). 110
14.1.3.2.2 ISDN User port FSM - LE (ISDN port). 110
14.1.3.3 Principles and procedures. 111
14.1.3.3.1 General. 111
14.1.3.3.2 Blocking. 111
14.1.3.3.3 Blocking request . 111
14.1.3.3.4 Co-ordinated unblocking. 112
14.1.3.3.5 Activation. 112
14.1.3.4 ISDN port FSM at the AN. 113
14.1.3.5 ISDN port FSM at the LE. 115
14.1.4 Performance monitoring aspects . 115
14.2 PSTN user port status indication and control protocol . 116
14.2.1 General aspects. 116
14.2.2 Events and function elements relevant for the control of the state machines . 116
14.2.3 PSTN user port FSM, AN (PSTN port) and LE (PSTN port). 117
14.2.3.1 Description of the states. 117
14.2.3.2 Definition of port control states. 117
14.2.3.2.1 PSTN user port FSM - AN (PSTN port). 117
14.2.3.2.2 PSTN user port FSM - LE (PSTN port). 118
14.2.3.3 Principles and procedures. 118
14.2.3.3.1 General. 118
14.2.3.3.2 Blocking. 118
14.2.3.3.3 Blocking request . 118
14.2.3.3.4 Co-ordinated unblocking. 119
14.2.3.4 PSTN port FSM at the AN . 119
14.2.3.5 PSTN port FSM at the LE . 119
14.3 Interface L1 maintenance requirements and protocol . 120
14.3.1 Events and failure reports. 120
14.3.2 Detection algorithm for events and signals. 121
14.3.3 V5.1 interface L1 FSM. 121
14.3.4 Requirements and procedures for the additional functions. 122
14.4 Control protocol. 122
14.4.1 Control protocol message definition and content . 122
14.4.1.1 PORT CONTROL message. 123
14.4.1.2 PORT CONTROL ACK message . 123
14.4.1.3 COMMON CONTROL message. 124
14.4.1.4 COMMON CONTROL ACK message . 124
14.4.2 General message format and information eleme
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