NI-9870 Specifications
- Updated2024-11-25
- 6 minute(s) read
NI-9870 Specifications
Definitions
Warranted specifications describe the performance of a model under stated operating conditions and are covered by the model warranty.
Characteristics describe values that are relevant to the use of the model under stated operating conditions but are not covered by the model warranty.
- Typical specifications describe the performance met by a majority of models.
- Nominal specifications describe an attribute that is based on design, conformance testing, or supplemental testing.
Specifications are Typical unless otherwise noted.
Specifications
The following specifications are typical for the range -40 °C to 70 °C unless otherwise noted.
Maximum baud rate | 921.6 kbps |
Maximum module throughput | 1.28 Mbps |
Maximum cable length | 250 pF equivalent |
Maximum RS232 Receive signal (RXD, CTS, DSR, DCD, RI) continuous voltage | ±8 V |
Data line ESD protection (human body model) | ±15 kV |
MTBF | 448,008 hours at 25 °C; Bellcore Issue 6, Method 1, Case 3, Limited Part Stress Method |
NI-9870
Pinout
The NI-9870 has four RJ-50 receptacles that provide connections for four RS232 devices.
RJ-50 Pin | Signal Name* |
---|---|
1 | No Connect |
2 | RI |
3 | CTS |
4 | RTS |
5 | DSR |
6 | GND |
7 | DTR |
8 | TXD |
9 | RXD |
10 | DCD |
*These signals are shared by all four RJ-50 connectors on the NI-9870.
The cables included with your kit convert the RJ-50 pinout to the standard NI pinout on a DB-9 male connector, as shown in the following table.

RJ-50 Pin | Signal Name |
---|---|
1 | DCD |
2 | RXD |
3 | TXD |
4 | DTR |
5 | GND |
6 | DSR |
7 | RTS |
8 | CTS |
9 | RI |
You must connect an external power supply to the NI-9870. This power supply provides the power for the RS232 transceivers on the module. You can use the included female four-position pigtail to connect to an external voltage source. The following figure lists the connections between an external voltage source (of +8 V to +28 V) and the NI-9870.

- V sup
- V sup
- COM
- COM
Figure 2 shows the method of power connection to the NI-9870 module. Attach an isolated power supply to the VSUP and COM terminals using the included pigtail.

Figure 3 shows how to use the optional Y-adapter (available at ni.com/serial) to connect power to more than one module using the same power source. One Y-adapter is needed for each additional module. Ensure that the power supply can handle maximum power requirements for all modules connected.

Power Requirements
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Required external supply voltage range (VSUP) | +8 to +28 V DC | ||||||
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Physical Characteristics
If you need to clean the controller, wipe it with a dry towel.
Weight | Approx. 154 g (5.4 oz) |
Safety Voltages
Maximum Measurement
Voltages
Connect only voltages that are within these limits.
RS232 Receive Signal-to-COM (RXD, CTS, DSR, DCD, RI) | ±25 V maximum, Measurement Category I |
RS232 Transmit Signal-to-COM (TX, RTS, DTR) | ±13.2 V maximum, Measurement Category I |
V sup-to-COM | ±28 V maximum, Measurement Category I |
Isolation
Voltages
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Measurement Category I
Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers equipment. This category is for measurements of voltages from specially protected secondary circuits. Such voltage measurements include signal levels, special equipment, limited-energy parts of equipment, circuits powered by regulated low-voltage sources, and electronics.
Environmental Guidelines
Environmental Characteristics
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Ingress protection | IP30 | ||||||||||||
Pollution Degree | 2 | ||||||||||||
Maximum altitude | 2,000 m | ||||||||||||
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To meet these shock and vibration specifications, you must panel mount the system.
Shock and Vibration
To meet these specifications, you must panel mount the system.
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Operating shock | 30 g, 11 ms half sine; 50 g, 3 ms half sine; 18 shocks at 6 orientations |