By Kent · Lock Depot Staff Writer

The access panel needs to know the door opened from the push bar

An integrator wiring a fire-rated stairwell or a monitored exit into an access control system runs into the same problem eventually: the panel needs to tell the difference between a legitimate exit through the panic bar and a forced or propped door. A plain 99 Series exit device doesn't report that on its own. It just lets people out. Getting that signal into the panel means specifying the device with the monitoring hardware built in from the factory, not bolting something on after the fact.

What RX actually is

RX stands for Request to Exit. It's a switch built into the exit device that Von Duprin factory-installs, and it fires the moment the push bar is depressed, sending a signal to the access control panel that says, in effect, "this is a legitimate exit, not a break-in." That signal is what lets the panel shunt the door alarm during a normal exit instead of tripping a forced-door alarm every time someone legally leaves the building.

QEL adds the other half: quiet, monitored latch retraction

Paired with RX on the RXQEL99 Series, QEL is Quiet Electric Latch retraction. Instead of a mechanical push-to-exit only, QEL lets the access panel electrically retract the latch itself, quietly, when a valid credential is presented on the outside, while the RX side confirms and monitors exit activity from the inside. Together, RX plus QEL gives full two-way integration on one exit device: monitored egress in one direction, electric latch release under access control in the other.

Exit-only vs. lever trim: pick the function the door actually needs

The RXQEL99EO is built as Exit Only: push bar operation from the inside, no outside trim, no cylinder required for that function, and free egress from the secure side at all times. That's the right call on a stairwell or back-of-house door where nobody needs to enter from the outside at all, only exit and be monitored doing it.

Where the door also needs a way in from the outside, Von Duprin builds the same RX plus QEL electronics into a lever trim configuration, ordered handed (LHR or RHR) to match the door swing. Confirm handing before ordering; a lever trim device built for the wrong hand won't mount correctly.

Grade 1, 24VDC, and why that's not a spec you improvise around

The RXQEL99 line is ANSI/BHMA A156.3 Grade 1 certified and runs on 24VDC. Grade 1 is the certification level required on most commercial life-safety doors, and the 24VDC input has to be fed from a power supply sized and regulated for the device, not scavenged off whatever transformer happens to be nearby. Undersized or unregulated power on an electrified exit device shows up later as intermittent latch retraction or an RX signal that doesn't fire reliably, which is a worse failure mode than the device simply not working at all, because it's inconsistent and hard to diagnose from the panel side.

This is still a rim exit device underneath the electronics

Strip away the RX and QEL wiring and the base hardware here is still a Von Duprin 99 Series rim exit device, sized for a 3' door, mounted on the surface of the door without requiring mortise prep or internal routing. That's worth keeping in mind on a retrofit: the same reasons a plain 99 series rim device is the easier install on a job with limited door prep still apply here. The electronics add the monitoring and access integration; they don't change how the device physically mounts to the door.

Hex key dogging, and why you may not want to use it on a monitored door

Like the base 99 Series, the RXQEL99 ships with hex key dogging standard, letting the latch be held retracted for periods when the door needs to stay open for traffic. On a door wired for RX monitoring, think through whether dogging the latch open defeats the purpose of the monitoring setup before doing it as a matter of routine. A dogged-open exit device isn't reporting anything meaningful to the panel because the latch state and the monitored condition are no longer tracking the door's actual use. That's a call for the facility's security policy, not a hardware limitation, but it's worth raising with the customer at spec time rather than after the panel starts logging events that don't match what's actually happening at the door.

Pro tip from the counter: field reversible handing on this series means a device ordered the wrong hand can usually be corrected on-site rather than sent back, which saves a install day when a door schedule gets revised late. For the fail-safe/fail-secure decision on the strike side of an access-integrated door, see our Von Duprin 6215 guide, and for latch retraction without the RX monitoring side, our QEL 9848 guide covers that narrower case.

Common questions

Do I need both RX and QEL, or can I order just one?

They're built together on this series as a matched electronic package. RX handles exit-side monitoring, QEL handles panel-controlled latch retraction from the outside, and most access-integrated exit devices are specified with both so the door is covered in both directions.

Does RX replace a separate door position switch?

No. RX confirms the push bar was operated, which is different information than a door position switch reporting whether the door itself is open or closed. Many monitored openings use both.

What voltage does the RXQEL99 need?

24VDC, fed from a regulated, properly sized power supply. Don't feed an electrified exit device off an undersized or unregulated transformer meant for a simple strike.

Can I get RX and QEL on a lever trim instead of exit-only?

Yes. Von Duprin builds the same RX and QEL electronics into lever trim configurations, ordered handed to match the door. Confirm LHR or RHR before ordering.

Should I dog the latch open on a door with RX monitoring?

Think it through with the customer first. Dogging the latch open means the device isn't reporting meaningful exit activity to the panel, which can undercut the reason the monitoring was specified in the first place.