2.7
SAE J1708 Configuration
The So ci ety of Auto mo tive En gi neers (SAE) J1708 in ter face is a varia tion of the RS- 485
in ter face which is used for “Se rial Data Com mu ni ca tions be tween Mi cro com puter Sys tems
in Heavy Duty Ve hi cle Ap pli ca tions”. It is be yond the scope of this docu ment to go into de -
tail on the J1708 speci fi ca tion. The PCM- DSPIO must be fac tory con fig ured for J1708 us -
age through the in stal la tion of a number of re quired ter mi na tion and fil ter ing com po nents.
The fol low ing il lus tra tions show the cor rect jump er ing, driver IC in stal la tion, DB9 I/O con -
nec tor pin defi ni tions, and ter mi na tion net work de tails for each of the chan nels when used
in J1708 mode.
2.7.1
Channel 1 - SAE J1708
981117
PCM-DSPIO/J1708 OPERATIONS MANUAL
Page 2-7
WinSystems - "The Embedded Systems Authority"
U2 - Not Installed
U5 - Installed
U6 - Not Installed
Jumper Positions
Driver IC Status
I/O Connector Pin Defs
N/C
TX/RX+
TX/RX-
N/C
GND
TX/RX+
TX/RX-
N/C
N/C
1 o
2 o
3 o
1 o
2 o
3 o
1 o o 6
2 o o 7
3 o o 8
4 o o 9
5 o
J5
J6
CH1 DB9
R15
R16
R17
TX/RX+
TX/RX-
R14
R9
4.7K
4.7K
4.7 OHM
4.7 OHM
C15 .0022 ufd
C11 .0022 ufd
Absent
vcc
