e-Navigation Netherlands
Published on e-Navigation Netherlands (https://www.e-navigation.nl)

Home > Text using 6-bit ASCII

Introduction/Additional information: 

This VDE Protocol Format may be used by applications that use VDE stations to transfer 6-bit ASCII encoded text. The text can be sent over VDE-TER or VDE-SAT as broadcast or addressed message. The parameter, “acknowledge required flag”, should be set to 0 when broadcast is used.

When long text strings are sub-divided, an 11-bit “text sequence number” is used. The text sequence number is used by the originating application to sub-divide the text and by the recipient application to re-assemble the text. The text sequence numbers for each sub-division should be selected to be contiguous and always increasing (110, 111, 112, …). If longer text strings are being transferred, the text sequence numbers should be chosen to associate correctly the sub-divided text with the correct text strings. For international compatible text or authentication / encryption, other VDES messages are defined below.

Permitted as from: 
01/12/2022
Registrant: 
IALA
Physical link: 
VDE-TER
VDE-SAT
Message number (0=VDES-VDE): 
0
DAC or VPFI: 
2
FI / Message ID: 
0
Technical point of contact: 

IALA

G1117-Ed3.0-VHF-Data-Exchange-System-VDES-Overview

State: 
proposal
Number of slots (max): 
1
FEC: 
No
Last modified: 
29/03/2023 - 15:07
Details: 

Parameter

Number of bits

Description

VPFI

16

2

Message ID

16

0

Acknowledge required flag

1

1 = reply is required, optional for addressed messages and not used for broadcast messages

0 = reply is not required, optional for an addressed message and required for broadcast messages 

Sequence number

2

0 – 3; see ITU-R M.1371-5, § 5.3.1, Annex 2

Text sequence number

11

Sequence number to be incremented by the application.

All zeros indicates that sequence numbers are not being used 

Last text in sequence

1

0: more text will follow

1: this is the last message in a sequence

Text string

VDE-TER: 6-6000

VDE-SAT: 6-

60000

6-bit ASCII as defined in ITU-R M.1371-5, Table 47, Annex 8. 

Spare bits

0-7

Byte boundary padding, value of the bits is set to 0;

Total number of application data bits

variable

 


Source URL (modified on 29/03/2023 - 15:07):https://www.e-navigation.nl/content/text-using-6-bit-ascii-3