JT/T 766.2-2019Shipborne terminal of BeiDou navigation satellite system - Part 2: Data exchange protocols (English PDF)

3.1 Terms and definitions

The terms and definitions defined in JT/T 766.1, as well as the following terms and definitions, apply to this document.

3.1.1

System acknowledgement

A confirmation given by the Beidou Satellite Navigation System distribution service platform to the sender (only a management terminal), indicating that the receiver has received the communication information sent by the sender.

3.1.2

Communication acknowledgment

An acknowledgment from the recipient to the sender, indicating that the recipient has received the communication information sent by the sender.

Note. The difference between a communication acknowledgment and a central acknowledgment is that the communication acknowledgment contains detailed parameters, facilitating communication control.

3.1.3

BeiDou navigation civil service platform

A platform that handles BeiDou satellite navigation positioning, timing, location reporting, SMS services; provides approved value-added services.

3.2 Abbreviations

The following abbreviations apply to this document.

ASCII - American Standard Code for Information Interchange

CGCS2000 - China Geodetic Coordinate System 2000

CRC - Cyclic Redundancy Check

ID - Identifier

UTC - Coordinated Universal Time

USB - Universal Serial Bus (USB)

4.1 RS-232 Interface

When the terminal uses the standard RS-232 interface, the interface signal definitions are shown in Table 1.

4.2 USB Interface

When the terminal uses the USB interface, the interface signal definitions are shown in

Table 2; a schematic diagram of the USB interface is shown in Figure 1.

6.1 Querying user information

6.1.1 Data format

The data format for querying user information is shown in Figure 2.

$CXYH, Card No., User type, Checksum< 0X0D> < 0X0A>

Figure 2 -- Data format for querying user information

6.1.2 Description

The description of the user information data format is as follows.

a) Card No.. Starts from 0, used in multi-card user machines, default 0;

b) User type. 0 represents this card, 1 represents a subordinate card.

6.2 Returning card user information

6.2.1 Data format

The data format for returning card user information is shown in Figure 3.

$BKYH, Card No., Card address, Platform broadcast address, service frequency,

Confidentiality flag, communication level, validity flag, checksum< 0X0D> < 0X0A>

Figure 3 -- Data format for returning card user information

6.2.2 Description

The description of the returned card user information is as follows.

a) Card No.. Starts from 0, used in multi-card user terminals, default 0;

b) Card address. Refers to the communication address of the terminal, represented by a decimal number, value "0000000" for no card;

c) Platform broadcast address. Refers to the ID number of the management terminal to which the terminal belongs, represented by a decimal number, value

"00000000" for no card;

d) Service frequency. Minimum time interval between two inbound requests from the terminal, range 0 ~ 60, value "000" for no card;

e) Confidentiality flag. 0 indicates no confidentiality, 1 indicates confidentiality;

f) Communication level. Default 3, see Table 4;

g) Validity flag. 0 indicates invalid, 1 indicates valid.

6.3 Returning subordinate card user information

6.3.1 Data format

The data format for returning subordinate card user information is shown in Figure 4.

$XSYH, Card No., Total frame number, current frame number, {User address}n,

Checksum< 0X0D> < 0X0A>

Figure 4 -- Data format for returning subordinate card user information

6.3.2 Description

User address, starting from 0, maximum 30 users per frame, the host continuously sends all frames.

6.4 Querying terminal status

6.4.1 Data format

The data format for querying terminal status is shown in Figure 5.

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