IEEE 1702:2011 pdf free download – IEEE Standard for Telephone Modem Communication Protocol to Complementthe Utility Industry End Device Data Tables
This standard does not specify the implementation requirements of the telephone switched network to the modem,nor does it include definitions for the establishment of the communication channel. The communication channel isconsidered available once the telephone connection has been successfully established and modems havesynchronized. The protocol specification for electric metering (PSEM) ldentification Service is required to establishthe protocol version and revision in use. Certain communication parameters may be modified through the use of thePSEM Negotiatc and Timing Sectup services in the Application Layer. These services are optional, and if notimplemented in the C12.21 Device or not used during actual communications，the communication channelparameters will remain at the default settings specified by this standard.Implementers are strongly encouraged toimplement these optional Application Layer services.
4.7.7.1 Channel Traffic Timeout
The C12.21 Device shall terminate communications after waiting some period of time for a valid PSEM Request orPSEM Response. This period of time is defined as the Channel Traffic Timeout.
4.7.7.2 Inter-Character Timeout
The recipient of the packet shall handle the case when the end of a packet is lost. Inter-Character Timeout is definedas the minimum amount of time the recipient shall wait between bytes within a packet when receiving data over thecommunication channel. The recipient shall wait at least this amount of time before it ceases to wait for theremaining bytes of the packet and sends a <nak>.
4.7.7.3 Response Timeout
The sender of the packet shall handle the condition when the <ack> or <nak> is lost.Response Timeout is defined asthe minimum amount of time the sender shall wait after a packet is sent to receive an <ack> or <nak> over thecommunication channel. If this amount of time elapses, the sender will send the packet again.
4.7.8 Turn-around Delay
The Turn-around Delay is the minimum delay the recipient must wait after receiving a packet and before sending apositive or negative acknowledgment.
4.7.9 Collision
lf the C12.2l Device detects a collision (i.e.,C12.21 Client and C12.21 Device are transmitting at the same time),the C12.21 Device shall cease transmission and wait for the transmission from the C12.21 Client.
4.8 Layer 1 – Physical Layer
The Physical Layer is not defined in this standard.
5.Compliance
A device is considered to be in compliance with this standard if all of the following conditions are met:
a) The C12.21 Device shall accept and act upon all required service requests defined in 4.2.If an optional service is not supported, the Ci2.21 Device shall respond with an <sns>. The minimum services supportedshall include ldentification, Logon, Logoff, and at least one (1) form of Read.Any service mentioned inthis document, if implemented,must comply with the ANSI Ci2.21 service description.
b) The C12.21 Device is compliant with ANSIC12.19 with respect to content and transmission of Table data.c)Layer 2 must be adhered to in its entirety.
d) A C12.21 Device is compliant with this standard if zero features (<feature>) are supported in the Identification Service.