1、NEMA Standards PublicationNational Electrical Manufacturers AssociationANSI C12.21-2006 (R2016)Protocol Specification forTelephone Modem Communication 2016 National Electrical Manufacturers Association ANSI C12.21-2006 (R2016) American National Standard for Protocol Specification for Telephone Modem
2、 Communication Secretariat: National Electrical Manufacturers Association Approved August 23, 2016 American National Standards Institute, Inc. ANSI C12.21-2006 (R2016) Page ii 2016 National Electrical Manufacturers Association NOTICE AND DISCLAIMER The information in this publication was considered
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12、nt. ANSI C12.21-2006 (R2016) Page i AMERICAN NATIONAL STANDARD Approval of an American National Standard requires verification by The American National Standards Institute, Inc. (ANSI) that the requirements for due process, consensus, and other criteria for approval have been met by the standards de
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19、et, Suite 900 Rosslyn, Virginia 22209 2016 National Electrical Manufacturers Association All rights, including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan Am
20、erican copyright conventions. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America ANSI C12.21-2006 (R2016) Page ii 2016 National Electrical Manufacturers
21、Association Foreword (This Foreword is not part of American National Standard C12.21) This standard provides an open-platform communications protocol for two-way communication with a metering device via a telephone modem. The protocol is written to conform to the OSI seven-layer stack. Long-time rea
22、ders of ANSI C12.21 will discover many editing changes to this version of the Standard. The Working Group chose to improve the clarity of the text as an aid to the reader while retaining the normative elements in the manner of previous publications. The 2006 revision of this standard was considered
23、in the context of the so-called “protocol suite” of ANSI standards: C12.18, C12.19, C12.21 and C12.22 (draft). Changes made were included only after assuring that existing devices implementing C12.21 would continue to remain compatible with the 2006 (R2015) revision. It is expected that the logoff s
24、ervice will become mandatory in the next revision of this Standard. Implementers are strongly encouraged to support this service to comply with this change. Suggestions for improvement to this standard are welcome. They should be sent to: National Electrical Manufacturers Association Senior Technica
25、l Director 1300 North 17thStreet Suite 900 Rosslyn, VA 22209 This standard was processed and approved for submittal to ANSI by Accredited Standards Committee for Electricity Metering C12. At the time the committee approved this standard, the C12 Committee had the following members: Tom Nelson, Chair
26、man Paul Orr, Secretary Organization Represented Name of Representative Organization Represented Name of Representative General Interest Elevate Energy L. Kotewa NIST T. Nelson ERCOT EnerNex LLC D. Tucker A. Snyder Power Measurements, LLC W. Hardy Future DOS R e.g., 1.2.840.10066.0., encoded as desc
27、ribed in ISO/IEC 8825-1, Basic Encoding Rules (BER). The last four (4) bytes of this identifier shall be identical to the values delivered in the C12.19 Table elements MANUFACTURER as defined in Table 00 of ANSI C12.19-1997 or the DEVICE_CLASS as defined by Version 2 of ANSI C12.19. := 0DHThe relati
28、ve encoding of the C12.19 Device Class relative to the universal identifier 1.2.840.10066.0, encoded as described in ISO/IEC 8825-1, Basic Encoding Rules (BER). The shall range between to 00Hto 04Hresulting in up to four (4) bytes being transmitted. These four (4) bytes shall be identical to the C12
29、.19 Table elements MANUFACTURER_ID as defined in Table 00 of ANSI C12.19-1997 or the DEVICE_CLASS as defined by Version 2 of ANSI C12.19, with assumed 00Htrailing pad. ANSI C12.21-2006 (R2016) Page 8 2016 National Electrical Manufacturers Association := Length of number of bytes that follow. This va
30、lue shall range between 00Hto 7FH := +Absolute object identifier encoded as described in ISO/IEC 8825-1, Basic Encoding Rules (BER). The size of this field shall not exceed 127 bytes. := +Relative object identifier encoded as described in ISO/IEC 8825-1, Basic Encoding Rules (BER). The size of this
31、field shall not exceed 4 bytes. := 07HAn Identifier that uniquely identifies a C12.19 Device in the application space of the C12.19 Device. This provides for early detection of the device identification element as per IDENTIFICATION of Table 05, DEVICE_IDENT_TBL, or DEVICE_ID found in Table 06 of AN
32、SI C12.19. The C12.19 feature shall be supplied when the C12.19 Device Table 05 or Table 06 are readable immediately following the Logon Service. When C12.19 Device identification is provided it shall not preceded features with codes that are less than 07H. := Length of number of bytes that follow i
33、n . This value shall range between 00Hto 7FH := Provides for disclosure of the C12.19 Device identification. := The character encoding format of the bytes which make up . Its interpretation shall be according to the relevant ANSI C12.19 data model referenced by the C12.19 registered Device Class fea
34、ture . When the feature was not supplied in this response, the value of shall be set to 01H, and shall be encoded according to ISO 7-bit coded character set for information interchange, per ISO/IEC 646 (1991). ANSI C12.21-2006 (R2016) Page 9 2016 National Electrical Manufacturers Association := *The
35、 C12.19 Device identification string encoded and transmitted according to . If the C12.19 Device ID_FORM in Table 00, is set to BCD then the BCD digits shall be transmitted as their text equivalent also encoded as per . For example, assuming that the C12.19 Device GEN_CONFIG_TBL.ID_FORM is BCD and t
36、he Device GEN_CONFIG_TBL.CHAR_FORMAT is ISO 7 bit ASCII, as per ISO/IEC 646 (1991), then the BCD digits 00H01H02H03H0AH04H0DH05H06H07Hshall be transmitted as the character sequence “123-4.567”. The C12.19 application shall logically pad this string with trailing spaces, as needed, to fill the identi
37、fication field width of the C12.19 Device. 4.2.2.4 Read Service The Read Service is identical to that in ANSI C12.18. At least one (1) form of the Read Service is required to be supported by a C12.21 Device. 4.2.2.5 Write Service The Write Service is identical to that in ANSI C12.18. The Write Servi
38、ce is an optional service. 4.2.2.6 Logon Service The Logon Service is identical to that in ANSI C12.18. The Logon Service is a required service. The Logon Service shall be initiated only by a C12.21 Client. 4.2.2.7 Security Service The Security Service is identical to that in ANSI C12.18. The Securi
39、ty Service is an optional service. The Security Service shall be initiated only by a C12.21 Client. 4.2.2.8 Logoff Service The Logoff Service provides for an orderly shutdown of the session established by the Logon Service. The Logoff Service is a required service. ANSI C12.21-2006 (R2016) Page 10 2
40、016 National Electrical Manufacturers Association Request: Following a Logoff Service request, the communication channel will return to the ID State, retaining the parameters previously established. := 52HResponse: The responses , , and indicate a problem with the received Logoff Service request. Th
41、e response indicates the acceptance of the Logoff Service and the cessation of the session established by the Logon Service. Prior to further data transfers with the C12.21 Device, the Logon Service must be reissued. := | | | 4.2.2.9 Authenticate Service The Authenticate Service is used to provide a
42、 two-way authentication with playback rejection during a session. It is recommended that the Authentication Service be used to complement the Security Service, not be used exclusively. The contents of the and fields are a function of the authentication algorithm used. This algorithm is returned by t
43、he Identification Service response. The Authenticate Service is an optional service. Request: := 53H:= number of bytes of the field. := +Information used to authenticate the initiator of this service. Response: The responses , , , and indicate a problem with the received Authenticate Service request
44、. The response indicates the authentication failure of the requester. The response indicates the Authenticate Service was successfully completed and the access permission associated with the field was granted. := | | | | | := Number of bytes of the field. := +Information used to authenticate the rec
45、ipient of this service. ANSI C12.21-2006 (R2016) Page 11 2016 National Electrical Manufacturers Association 4.2.2.10 Negotiate Service The Negotiate Service is identical to that in ANSI C12.18. However, the field of the request shall be ignored because in this standard the data rate is established b
46、y the modem. The Negotiate Service is an optional service. 4.2.2.11 Wait Service The Wait Service is identical to that in ANSI C12.18. The Wait Service is an optional service. 4.2.2.12 Terminate Service The Terminate Service provides for immediate transfer to the Base State. All parameters return to
47、 their default values. The Terminate Service is an optional service. Request: := 21H Response: The responses and indicate a problem with the received Terminate Service request and the channel retains its negotiated settings. The response indicates the Terminate Service request was accepted and the c
48、hannel will return to default settings as stated in Section 4.7.1.2, Variable Settings, upon receipt of a positive acknowledgment. := | | 4.2.2.13 Timing Setup Service The Timing Setup Service provides the mechanism for reconfiguring time-outs, delays and retry attempts from the default values speci
49、fied in this standard. The Timing Setup Service is an optional service. The Timing Setup Service is initiated by the C12.21 Client. Request: := 71H:= Channel traffic time-out in seconds := Inter-character time-out in seconds := Response time-out in seconds ANSI C12.21-2006 (R2016) Page 12 2016 National Electrical Manufacturers Association := Maximum number of retry attempts Response: The responses , , , and indicate a problem with the received Timing Setup Service request and the timer parameters will maintain the
