Frequently Asked Questions

Technical Questions & Answers About Versus RTLS

Do you have questions about how we use Infrared and Radio Frequency Identification in our Real-time Locating System? How long badge batteries last? What kind of preventative maintenance is needed? These and other technical RTLS questions are answered below.

How does Versus identify the precise location of people and assets in real-time?

Versus combines invisible Infrared (IR) light and the communication capabilities of radio frequency identification (RFID) to provide the most precise locating technology available to healthcare. Badges (worn by patients and staff) and tags (affixed to equipment and charts) emit Infrared and RFID signals which contain unique identification codes. Ceiling-mounted sensors receive the Infrared and RFID signals, accurately locating the tag. There can be no “false-positives” (i.e. no reports of a signal in a location where a signal is not present) because the sensor is stationary and receives signals based solely on signal presence. Rules-based software disperses location information throughout Versus’ system and to 3rd-party systems for viewing, reporting and automation.

Sometimes, it helps to see it. Visit our technology page for a visual and more details.


What is Infrared light—and where will I find it?

Infrared light is a radiation source similar to light, except that it is non-visible and most often detected as heat. Infrared has a lower frequency (or longer wavelength) than visible light, but a higher frequency (shorter wavelength) than microwaves or radio waves.

Infrared light is most often associated with heat sources—namely, the sun—and everyday items such as remote controls, digital cameras and night vision equipment. Though some like to call Infrared “old” technology (old as the sun!), most will recognize that Infrared is a basic component of some of our most advanced national defense and communication systems— thermal imaging, homing devices and fiber optic cabling.

Within healthcare, Infrared is commonly used for non-invasive diagnostics (thermography, CT scans and some MRIs) to achieve the impressive results of LASIK eye surgery and radiant heat therapy. Among dentists, Infrared light is used to whiten teeth and make some treatments such as drilling and lesion removal faster, safer and less painful.


Is Infrared safe?

Infrared is one of the many forms of light on the electromagnetic spectrum that is not visible to the human eye. The electromagnetic spectrum includes gamma rays, X-rays, ultraviolet, visible, infrared, microwaves, and radio waves. The Infrared signal transmitted by the Versus badge is similar in duration and power to the Infrared signals transmitted by ordinary remote controls that operate TVs and DVD players—signals which have never demonstrated any danger to humans during decades of use.

An independent study was conducted in August 2000 by the United States Department of Health and Human Services regarding the safety of Infrared light. The statement, issued by the National Institute for Occupational Safety and Health, concludes that the Infrared emitted from a Versus badge “shows no hazards to the eye” and “such diffuse IR emitted by IR LEDs has never been an eye hazard.” A copy of the two-page report is available upon request.


What makes Infrared so well-suited to RTLS?

Infrared light is easily transmitted and received. An object either emits Infrared light or it doesn’t. (All objects with a temperature above absolute zero do.) A receiver either receives the light or it does not. This means that with Infrared you can apply an “It is or it isn’t” philosophy to the work you are doing. It (whatever “it” may be) is either there—or it isn’t. Infrared locating offers a straightforward, highly accurate methodology, so there’s no need for calculations or algorithms. No games, no guessing. With such a low, virtually non-existent failure rate, Versus offers clinical-grade accuracy and a “No False Positives” guarantee.

Additionally, Infrared light is a great way to convey information. Versus’ transmission packets carry only a small amount of data and transmission occurs quickly (within 1/60th of a second). Each Infrared signal transmits a unique identifier, which can be both focused and directed. Infrared receptors, which can be focused to allow smaller reception range, are highly sensitive and are equipped to convert light energy to electrical signals. Thus, a single sensor can identify multiple data packet transmissions in a near simultaneous fashion.


Why is Infrared RTLS so prolific within healthcare?

Versus has been around since 1988 and began providing our Infrared-based RTLS to clients in 1991. More than 20 years later, our first customers still use the system on a daily basis. As a result of direct sales and an extensive network of dealers and resellers, the Versus system is installed in nearly 700 hospitals and clinics and covers more than 220,000 critical care beds. We estimate over 80% of automated nurse call systems within the United States are supported by location data determined and disseminated by Versus. You may be familiar with Versus through our nurse call system partners: Rauland-Borg, SimplexGrinnell, Ascom (formerly GE Healthcare/Dukane), Tek-Tone and West-Com.

Infrared RTLS has a rich history in healthcare; no one can deny the considerable successes our clients experience with Versus RTLS. Our clients are enjoying clinical-grade location accuracy throughout their organizations; they’re automating patient flow, bed management, hand hygiene compliance, nurse call, other HIT, and a number of process-specific workflows. Clearly, they’re doing more than just basic asset tracking or temperature monitoring. Vendors focused on these ventures alone are misleading the industry as it relates to RTLS’ potential to transform patient care. We invite you to learn more about our clients’ successes in our Proven Success section.

Versus owns nine patents that provide for accurate, timely location data and its communication. As other vendors are unable to offer the same technology as part of their RTLS, they are forced to malign the technology as “old” or “line of sight.” We understand. We’ve been around a long time. We’ve seen many technologies fail and many vendors come and go. That said, we know what works and what doesn’t, and we are happy to educate our customers. We also thoroughly understand Infrared light and how to apply it for accurate locating. So, when questioned, we point to our experience, system longevity and our many happy clients—as well as poignant differences between what our customers are achieving with accurate RTLS and clinical automation and what’s commonly being done, and allow educated consumers to draw their own conclusions.


Why does Versus utilize Infrared for locating rather than other technologies such as RFID
(Wi-Fi, ZigBee or Ultra Wide Band) or ultrasound?

The Versus system is designed to a clinical-grade standard. Our RTLS offers the safest, most efficient, most consistent, most reliable and most cost-effective mechanism to achieve the level of accuracy necessary to automate workflows and other clinical information systems.

We rely on this proven technology because it works. We researched and tested many other technologies, including several not mentioned here. Infrared wins out because it meets the clinical-quality standard, requires little-to-no maintenance and the cost to implement vs. total cost of ownership is exceedingly low.

Here are some of the reasons we prefer Infrared:

  • Automation requires accuracy.
  • No false reports. Infrared cannot locate a person or item in a location where the person or item is not. A signal must be definitively received. Complex algorithms to estimate location such as received signal strength indication (RSSI) and time difference of arrival (TDOA) are not factors.
  • You can ‘miss’ a location report knowing you’ll have another one momentarily—but: YOU CAN NEVER PERFORM AN ACTION BASED ON A FALSE LOCATION REPORT! If you cancel a patient call in Room 206 when the nurse was really in Room 208, your staff will not rely on the system and your investment will fritter away. More importantly, this is a patient safety issue.
  • Location is determined based on signal receipt at a fixed location. Two main benefits:
  • Tags are not expected to locate themselves by ‘asking’ where the sensors are and then determining which sensors ‘answer’ the loudest.
  • The fixed location of a Versus sensor has a commonly known identifier such as Room 206. Therefore, the location report is returned as Room 206, not as an approximated X,Y coordinate.
  • Other systems rely on RSSI and TDOA calculations to estimate location and then project the resulting X,Y coordinate onto a 2-D floor plan. As signal strengths are in constant flux and they cannot definitively demarcate walls and other bounding structures, coordinate-based location returns often place the tracked item on walls, other floors and even hovering outside the building.
  • Light travels faster than sound. Light waves are electromagnetic and move freely through open space.
  • Sound waves are mechanical and require additional energy to push them out where they need to be. They can also be easily disrupted by any nearby generator of high frequency sound waves (i.e. “anything that makes noise”). This noise can distort or even totally block the location data.
  • Near 100% signal reflection, a result of diffused Infrared, works in the system’s favor by allowing light waves to “paint” the interior of a target location—but not seep through walls or around corners as sound waves do.
  • No signal leakage or attenuation: common interior surfaces reflect Infrared light with a high degree of efficiency.
  • No electromagnetic interference: Infrared light cannot interfere with RF spectrum communications.
  • Safe and accepted worldwide: Infrared radiation has coexisted with us throughout recorded history.


How does Versus utilize RF signals? Are they safe?

Radio frequency is the type of energy radio and TV stations emit into the air. Cardiac monitors and other healthcare wireless telemetry devices also emit radio waves. Versus uses the RF signal to identify a zonal area, to enunciate the call/alert message when a button is pressed on the badge, and as a general beacon to tell the system that a badge is active.

RF signals are regulated by the Federal Communications Commission (FCC) and all Versus RF products are FCC-approved and operate at 433MHz (a band approved for clinical Active RFID operations).


Are there interference issues among the Versus RTLS and sensitive medical equipment, patient devices or other items/systems with the healthcare environmental?

No. Versus’ RTLS does not interfere with medical equipment, patient devices (neither pacemakers, heart monitors nor other telemetry equipment), microwaves, Wi-Fi, nor any other item in the healthcare environment.

To date, with 220,000 critical care beds covered by Versus RTLS and more than 16.5 million patients tracked annually, Versus has had no reports of interference with medical equipment. Considering we utilize Infrared light with a modulation frequency slightly higher than the remote controls that operate common TVs and VCRs and that the RF component of our system operates at a frequency of almost half that of cell phones (similar to key-fobs used to lock or unlock car doors from a distance), this is not an unexpected finding.

Versus’ Infrared-based locating system is incapable of causing undesirable side effects on medical equipment. While we utilize RF, these transmissions are very low power RF transmissions that are used to supervise the operation of the Infrared transmissions. Use of RF in a supervisory capacity to transport data, as Versus uses it, only serves to enhance patient safety. This has been verified by multiple outside laboratories. Additionally, our RF transmissions are approved by the Federal Communications Commission as having complied with the periodic operation limits set forth in Section 15.231(e) of the Rules, 47 C.F.R. S 15.231(e). This reduces the possibility of their interference with medical equipment to nearly zero.


What is the maximum read range between Versus tags and sensors? And why does Versus focus sensors to limit the read range?

The Infrared component of Versus badges and tags is designed to emit to a maximum distance of 16 feet in all directions. Sensors, in turn, have a maximum receipt range of 16 feet, but this can be focused to as little as 12 inches. Versus could have chosen a more powerful output setting allowing the Infrared light emitted from badges and tags to extend across greater distances, but doing so would counter the excellent system design wherein the Infrared signal is meant to be received by a single, fixed sensor.

The Versus system is intentionally designed NOT to allow overlap among areas defined as a location. We focus sensors and allow space between each sensor’s signal receipt areas to help ensure each tag’s unique Infrared signal is received at only one sensor. The location report is based on that signal’s receipt at a fixed, commonly known sensor location. (If the Infrared signal is received at two known locations, and one was the existing location from the previous report, the location report will remain the same until the signal is received at only a new location.) We are able to do this because the location report from the badge occurs so frequently.

It is important not confuse greater read range with greater accuracy. Defining a tag’s location based on a fixed, strategically placed sensor and its receipt of a unique Infrared signal offers exceptional accuracy. Analyzing various location reports to determine location will never produce a location report as accurate as simply accepting a definitive location report. Other systems depend on heavy sensory network overlap in order to analyze time difference of arrival (TDOA) or received signal strength indicators (RSSI) before returning a location report.


What minimum conditions must be met to ensure the Infrared signal from the badge is received by the sensor?

The Infrared signal must be exposed to the sensor. The Infrared LED placement within the Versus badge is designed to emit signals through the window of the badge housing. In reality, even the housing doesn’t completely block the Infrared signal, but it does help to reduce the strength of the signal and focus the greatest amount of Infrared light through thewindows on the front of the badge. The Infrared signal is not a laser beam, but rather a more diffused circular burst radiating from the badge up to the ceiling-mounted sensor. It is similar in coverage to a burst of light from a flash bulb.

Once the short burst of Infrared light is exposed to the system, the clinical environment helps ensure the signal reaches the sensor. If not received directly via open air, the Infrared light will reflect off of other surfaces such as walls, floors, ceilings and equipment before reaching the sensor’s reception area.

When worn as recommended (high on the body, clipped to the lapel), there is little chance the signal will be completely blocked from the system. In the event that a signal is blocked, a second signal will pulse just three seconds after the first—giving Versus another opportunity to capture and report location. Additionally, Versus maintains the “last known location” at all times and, by utilizing RFID in a supervisory capacity, we always have general location information available as well.

The most important thing to remember regarding signal receipt is that Versus will never receive or relay a false report.


What is the maximum number of tags the Versus system can track concurrently?

Technically speaking, in any given moment a single sensor can receive only one Infrared signal. However, a single sensor can read up to 50 tags per second, 150 tags in a three-second transmission window, or 3,000 tags per minute.

Versus badges are available with up to 1 million unique IDs. Additionally, the Versus RTLS architecture supports a combination of 2 billion active and passive locating devices in a transaction platform. This is very important as it allows our clients to deploy the Versus software as an effective RTLS middleware platform that will accommodate combinations of active or passive RFID, IR, Sonic or user-definable locating devices from not only Versus but other RTLS and RFID device manufacturers and track virtually any number of items.

There’s a limit to the number of sensors that can be deployed on any given system, but that number is in the tens of billions. As most enterprise installations have required fewer than 3,000 sensors, we’ve never come close to hitting this number.


How much bandwidth is required by the system?

The amount of bandwidth Versus’ RTLS utilizes is directly related to the size of the system. Clients can expect that 100 badges (in use 24 hours a day, 7 days a week) will require about 25 kilobits/second—a minimal impact on the existing infrastructure. The above estimate is based on patient and staff locating. Equipment tracking applications will typically require even less bandwidth.


What ongoing preventive or system maintenance is required?

Versus utilizes a mix of hardware and software diagnostic tools to provide continuous monitoring of the sensory network, complete with rules-based alerts and reports to notify users of any issues that arise. Versus technical support also dials in remotely on a monthly basis to determine overall health of the system.

Hardware: The most frequent maintenance involved with the Versus RTLS is the ongoing assignment of badges to personnel, patients or equipment, and the deletion of former badge assignments from the system. Badge assignment can occur automatically through integration with a system such as ADT. Badges can be scanned or keyed in and associated with existing data. Badge assignments can be deleted automatically simply by using the Versus Badge Drop Box—which also removes the patient from software views upon discharge. Additionally, badge batteries require periodic replacement. Versus provides a low battery alert message, as well as a suite of tools for system testing.

Software / Server: Versus estimates 1/8 FTE per month for general server maintenance, SQL data maintenance and software updates.


How long do badge batteries last?

Battery life expectancy is a direct result of system design; Versus’ RTLS is designed for high accuracy, reliability and timeliness. Battery life is affected by time spent in motion and the badge flash rate (how often it emits signals). Versus has determined that, for most applications, our standard 3-second flash rate for staff/patient badges (plus “bursts” whenever a badge button is pressed) and a 3- to 15-second flash rate for equipment tags provides the ideal balance between performance and battery life. Based on this configuration, clients using our Extended Life (XL) badges and sensory network can reasonably expect to attain an 8- to13-month battery life from badges and 16 to 28 months from asset tags.

Note: Flash rates can be customized when tag order is placed; some applications may require special flash rates.


What do you do with location data once you collect it?

There are so many options! Basically, we display it in real-time on dashboards, floorplans or list views; store it for historical reporting; act on it to provide alerts and process automation; and share it with other systems.

For more detail, explore the Advantages Demo or read more about Versus Advantages™ here.


How do you integrate real-time data to other clinical information systems?

Versus provides an integration framework that allows customers to exchange data contextually and automatically between the Versus platform and other enterprise-wide applications in real-time. Raw location data from the sensory network is not accessible; however, with the interface protocols below, it is also not necessary.

Interface Protocols
Usage (Protocols selected based on communication needs and requirements)
HL7 Versus frequently integrates with other healthcare systems via the HL7 standard protocol. HL7 v2.3 and v3.0 Messages and Segments are supported.
XML and Web Services Versus can deliver and receive structured XML when exchanging data between systems. A number of standard Web Services can be made available that allow data communication via SOAP 1.1, SOAP 1.2, HTTP GET and HTTP POST methods. The Versus Web Services provide a robust mechanism to seamlessly communicate with other systems.
SQL SQL access directly to the Versus database allows for data integration to logged tracking information such as historical location and asset ID tracking, workflow events and process intervals.
TCP/IP Socket The Versus system is based on TCP/IP passing data through open sockets. Because of this, it is an extremely “open” system, meaning that not only can Versus clients receive their data on this connection, but so can any application that is TCP/IP aware.


Still have questions?

Please contact us!

Did you know?

  • More than 700 healthcare facilities around the world benefit from Versus’ real-time location information
  • Nearly 2 million Versus RTLS components help facilities world-wide to find the resources they need
  • Versus tracks more than 1 million patients annually
  • 80% of automated nurse call systems are integrated with the Versus RTLS
  • Versus covers 220,000 hospital beds
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