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July 2025
U2121A
Keysight/Agilent U2121A, 32 I/O Lines, 0–24 VDC Input Voltage, USB Digital I/O Module
Actual item may vary if no part number is provided on quote request.
✔ 2 Year Warranty Included
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Andrew Gar**** Verified Buyer
" Amazing to work with and had my order within 1 week after purchasing with all NI certs and data that were needed. "
March 2025
Said Sai**** Verified Buyer
" Competent contact for highly specialized components. The support team is very knowledgeable. Many thanks for the help and the fast shipping! "
January 2025
Bob C**** Verified Buyer
" Jason was able to get our emergency situation taken care of quickly and professionally. "
May 2025
Gregg Flecki**** Verified Buyer
" Great service and great products. This is my 2nd time using Apex Waves, truly impressed. "
January 2025
Carol Zimme**** Verified Buyer
" Very responsive and helpful, competitive pricing. Good source! "
July 2025
Andrew Gar**** Verified Buyer
" Amazing to work with and had my order within 1 week after purchasing with all NI certs and data that were needed. "
March 2025
Said Sai**** Verified Buyer
" Competent contact for highly specialized components. The support team is very knowledgeable. Many thanks for the help and the fast shipping! "
January 2025
Bob C**** Verified Buyer
" Jason was able to get our emergency situation taken care of quickly and professionally. "
May 2025
Gregg Flecki**** Verified Buyer
" Great service and great products. This is my 2nd time using Apex Waves, truly impressed. "
January 2025
Keysight/Agilent U2121A USB Digital I/O Module
The Keysight/Agilent U2121A USB digital I/O module offers 32 optically isolated lines of I/O, 16 input channels, and 16 output channels all via an interface compliant with full-speed USB 2.0 as well as USB-TMC/USBTMC. All of the input channels can read from 0 to 24 V DC; the output channels can drive loads up to 24 V. Optic isolators prevent damage from voltage spikes on the field side. Power-up states for the programmable outputs are defined by the designer to ensure proper logic levels. If there is loss of communication from the host PC, then a watchdog timer will force the outputs into a safe state. Edge detection and a configurable digital filter for noise suppression make this product suitable for use in harsh electrical environments for actuator control, sensor monitoring, encoder reading, etc.
Standard software support for the Keysight U2121A includes Keysight's VEE software, National Instruments' LabVIEW software, and Microsoft's Visual Studio. In addition to these proprietary software programs, the Digital I/O Module also supports standard SCPI commands, which allow for easy integration into test sequences. Since the USB interface does not require any additional PCI slots, it allows for very fast development of benchtop validation setups, production test jigs, laboratory data loggers, etc., where high-voltage isolation between controller and field devices is required. The onboard digital filter and edge detection reduce or eliminate the need for external signal conditioning when debouncing mechanical contacts or capturing fast pulse trains.
For RF switching applications, the U2931A driver option expands the functionality of the U2121A by providing five switch channels pre-configured for use with either Keysight's N1810, N1811, or N1812 coaxial switches. However, each channel can only be used to control one type of switch at any given time. A complete kit of this module includes a driver interface module, a 37-pin D-SUB cable with branching terminal blocks on four ends, a 10-pin to D-SUB adapter, and a 24V DC power adapter. This integrated solution eliminates the need for separate switch driver boxes, thus simplifying small test systems used for wireless device validation, antenna multiplexing, and automated spectrum monitoring. The use of terminal block connections and the adapter cable has also simplified wiring to provide isolated control signals directly to the switches.
| Model Name | U2121A |
|---|---|
| Part Type | USB Digital I/O Module |
| Manufacturer | Keysight |
| Legacy Manufacturer | Agilent |
| Channel Config | 32 isolated (16 input, 16 output) |
| Input Voltage | 0–24 VDC |
| Output Load | 24 VDC max |
| Sink Current | 800 mA/ch, 1600 mA total |
| Interface | USB 2.0 FS, USBTMC |
| Isolation | 2000 Vrms |
| Filtering | Programmable debounce/glitch |
| Features | Watchdog, power?up presets, edge detect |
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