B&B Electronics RS-232 to J1939 Converter CE 1939STB - Manual (Page 9)

1939STB4600 Manual 7
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91 792444 – Fax +353 91 792445
Control Byte 4
When control byte 3 is set to “external commands” (bit 4 set to 1), nibble
1 of control byte 4 is used to tell the J1939 in which message slot location (1
through 15) to place the message data. NOTE: Message location number 15
is receive only.
When control byte 3 is set to “ internal commands” (bit 5 set to 1), nibble
1 of control byte 4 has the following functions:
Nibble 2 of control byte 4 is reserved for future use and is set to 0.
Table 7. Byte 4
Nibble 2 Nibble 1
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Table 8. Nibble 1 Bit Values
Nibble 1 Value Function
0001 Display vender number & version
0010 Set baud rate, stop, start bits
0100 Not used
1000 Not used