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App Notes

Software & Driver


17.0 DB15

Number of Pins: 15

Screw type: #4-40

Contacts: Gold-coated

Form factor: D-Sub

The DB15 connector brings out 12 additional digital I/O. It has the potential to be used as an expansion bus, where the 8 EIO are data lines and the 4 CIO are control lines.  EIO0-CIO3 can also be addressed as DIO8-DIO19.

EIO0-EIO7  aka DIO8-DIO15
CIO0-CIO3  aka DIO16-DIO19

The CB15 is a connector board that provides convenient screw-terminals for the DB15 lines, but the CB15 is not required to access I/O on the DB15.  Any method you see fit can be used to access the DB15 lines.

These 12 channels include an internal series resistor that provides overvoltage/short-circuit protection. These series resistors also limit the ability of these lines to sink or source current. Refer to the specifications in Appendix A-2. All digital I/O on the U6 have 3 possible states: input, output-high, or output-low. Each bit of I/O can be configured individually. When configured as an input, a bit has a ~100 kΩ pull-up resistor to 3.3 volts. When configured as output-high, a bit is connected to the internal 3.3 volt supply (through a series resistor). When configured as output-low, a bit is connected to GND (through a series resistor).

Table 17-1. DB15 Connector Pinouts

DB15 Pinouts        
1 Vs   9 CIO0
2 CIO1   10 CIO2
3 CIO3   11 GND
4 EIO0   12 EIO1
5 EIO2   13 EIO3
6 EIO4   14 EIO5
7 EIO6   15 EIO7
8 GND      


Figure 17-2. Standard DB15 pin numbers looking into the female connector on the T7.


The CB15 terminal board connects to the DB15 connector. It provides convenient screw terminal access to the 12 digital I/O available on the DB15 connector. The CB15 is designed to connect directly to the DB15, or can connect via a standard 15-line 1:1 male-female DB15 cable.


The RB12 relay board provides a convenient interface for the T7 to industry standard digital I/O modules, allowing electricians, engineers, and other qualified individuals, to interface a LabJack with high voltages/currents. The RB12 relay board connects to the DB15 connector on the LabJack, using the 12 EIO/CIO lines to control up to 12 I/O modules. Output or input types of digital I/O modules can be used. The RB12 is designed to accept G4 series digital I/O modules from Opto22, and compatible modules from other manufacturers such as the G5 series from Grayhill. Output modules are available with voltage ratings up to 200 VDC or 280 VAC, and current ratings up to 3.5 amps.


The OEM T7 has a separate header location to bring out the same connections as the DB15 connector. This OEM header location is labeled J2. The J2 holes are always present, but are obstructed when the DB15 connector is installed.   Find the pinout, and other OEM information for J2 in OEM Versions.