1939STB4600 pg. 1/1
B&B Electronics November 2000
This product designed and manufactured in USA of domestic and imported parts by
RS-232 to SAE J1939 Converter
Model 1939STB
Description
The 1939STB provides a communication link between a host computer RS-232 port and a SAE-
J1939 bus. The 1939STB complies with the SAE-J1939/11 specification and supports the physical
layer. Although SAE-J1939 is CAN based, the 1939STB has no support for standard CAN frames
(11 bit). The baud rate on the J1939 port is fixed at 250 kbps. The RS-232 side supports baud rates
of 9600, 19.2k, 38.4k, 57.6 kbps.
Communication between the host PC and the J1939 bus employs control headers for
transmission and reception from the SAE-J1939 bus. The control headers break down as follows:
Transmit Header
The transmit header has 4 bytes for control, and 4 to 16 bytes of data arranged as shown in the following table:
Byte 1
Byte 2
Byte 3
Byte 4
Up to 16 Bytes data
81
21
Function code // Message number
Reserved // # of bytes in message
---
Function Codes:
0001 = Move information in data field to the J1939 bus
0010 = Internal commands; (vendor code; set baud rate (RS-232 port))
Byte
Function
Byte
Function
0
Message control byte 1 (internal)
8
Data
1
Message control byte 2 (internal)
9
Data
2
Priority (3bits); data page (1bit); PF (4bits)
10
Data
3
PF cont. (4bits); PS (4bits)
11
Data
4
PS cont. (4bits); Source Address (4bits)
12
Data
5
Source Address cont. (4bits )
13
Data
6
Message Configuration (internal)
14
Data
7
Data
15
Reserved
Reception Header
The reception header uses 2 bytes for control and up to 16 bytes of data.
Byte 1
Byte 2
Up to 16 bytes of data
42
Message type // Bytes in message
---
Message Type:
0000 = data from J1939 bus
0001 = error message (data field contains messages function)
WARNING!
This Model 1939STB Converter Module allows you to connect to active SAE J-1939 networks. It is possible that your
transmissions through this converter module could cause malfunction of the network operation, damage to the software or
equipment, or bodily harm.
Do Not Transmit Any Messages to The Network
without a complete understanding of the operation of the network.
B&B Electronics Mfg. Co. specifically disclaims any responsibility for damage or injury to software, hardware, equipment or
persons as a result of using this product.
Physical Description
Length:
5.3 in (134 mm)
Width:
2.8 in (70 mm)
Height:
1.0 in (25.4 mm)
Serial Connection:
DB9 female, DCE
SAE-J1939 Connection:
Terminal blocks
Power Connection:
Terminal blocks
Temperature:
0 to 70
o
C
Input Power Requirement:
10 to 42 VDC
Meets physical layer SAE-J1939/11
Fully compatible with ISO 11898-24v standard
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