Offline PCR User's Guide

A walkthrough of all of the features and functionality offered in the Offline PCR, as well as how to use it

For crew members who run calls in areas where a wireless signal is often unavailable, AngelTrack's Offline PCR provides relief.

The Offline PCR is a WebAssembly that runs on any computer or mobile device that has a modern compliant web browser. It offers single-click launch, running right from AngelTrack without any pre-installation or ongoing maintenance. It offers the same friendly PCR user-interface as normal (online) AngelTrack. Crews can run it whenever they like without any retraining. It collects run-call data, electronic signatures, geolocation, and basic PCR forms, even though the wireless signal may be lost for up to an hour.

No installation necessary

Crews can use the Offline PCR at any time, with no need to install something on their mobile devices. They need only click the SatelliteDish satellite dish icon, in the top-right corner of all AngelTrack crew pages.


  • Nothing to install or update; it is one-click launch right in the web browser.
  • "Bring Your Own Device": It can run on any modern device that has the Chrome, Edge, or Safari browser. It may also work in the Firefox browser, but this is not guaranteed.
  • Ability for all crew members to use any combination of online and offline PCRs simultaneously.
  • Automatic assumption of the user's current AngelTrack login, so that no re-login is necessary.
  • Can collect data for up to an hour without a wireless signal, and send it all up to the server once the signal returns.
  • Seamless one-click switching back and forth from online PCR to offline PCR and back again.
  • Looks and works just like the online PCR, so very little retraining is necessary.

How It Works

The Offline PCR uses Microsoft's Blazor™ technology to run right inside the user's web browser. This is known as a "WebAssembly".

Because the Offline PCR is running in the web browser, it automatically assumes the user's AngelTrack credential, so that the user need not login again.

The app monitors the device's wireless signal, and automatically synchronizes with the server whenever it can.

No installation necessary

Because the Offline PCR is a WebAssembly that runs in the user's web browser, it requires no pre-installation.

Nor does it ever need to be updated; whenever the crew member launches the Offline PCR, the latest version is pulled down from the AngelTrack server.

Outbox / Queuing of changes

All data input by the user is queued up in the Outbox, as indicated by the Upload.small cloud icon in the Offline PCR's top right corner. The user can click the cloud icon to review the contents of the Outbox.

Whenever the device has a wireless signal, the Offline PCR will automatically send to the server everything in the Outbox. It will then pull down new status information about the current user's assigned calls.


AngelTrack's Offline PCR has the following limitations:

  • It must occasionally have a wireless signal -- at least once an hour -- in order to synchronize. After one hour without a signal, it will not let the crew input additional data, until it has a chance to synchronize again.
  • Its queue of data awaiting upload is stored in the browser on the user's device, and so the data could be lost if it doesn't get a chance to upload it before the user forcibly closes the browser.
  • Because the Offline PCR piggybacks on the user's current AngelTrack credential, if the user logs out from AngelTrack in another browser tab, the Offline PCR will lose its authentication, and will not be able to synchronize until the user logs it back in.
  • It lacks the full functionality of the normal (online) PCR. Instead, it has a subset of PCR functions sufficient for running calls, on the understanding that crews will finish and submit their reports later, back at the station. See below for its full feature list.
  • Like the rest of AngelTrack, it supports the Chrome, Edge, and Safari web browsers. It will probably work in other browsers too, but your mileage may vary.
  • The mobile device's clock must be accurate within two minutes of the AngelTrack server's clock. Normally, mobile devices automatically set their clocks by means of the cellular network, but it is possible that a laptop or toughbook without automatic clock-setting could try to use the Offline PCR. If the mobile device's clock differs more than two minutes, then the Offline PCR will pause, and ask the user to synchronize the device's clock before proceeding.
  • In the Safari web browser on Apple devices, date-time fields do not presently support the "seconds" value, they only support hours and minutes. If there is date-time data that must be recorded with a precision of seconds, then the user must switch to a different browser, or switch back to the online PCR.

PCR Feature Subset

The Offline PCR is a subset of AngelTrack's full online PCR. It contains the following PCR functions:

  • Basic login / logout / user status.
  • Light-mode and dark-mode.
  • Timeclock status and posting location.
  • Continuous geolocation with automatic reporting to the server when connectivity is available.
  • The run-call page, including:
    • Time punches;
    • Odometer readings;
    • One-click launch of streetmap app for driving directions;
    • The ability to simultaneously run two different calls; and
    • Dispatch self-close (aka Unattended Mode) where permitted.
  • Electronic signature collection, including automatic back-dating if a signal is not obtained until later.
  • Electronic PCS form with geolocation and e-signature.
  • Electronic McPAN form with geolocation and e-signature.
  • Add and edit vital signs, with age-sensitive physiology highlighters.
  • Review and edit patient demographics.
  • Review and edit patient billing data.
  • Review and edit patient PMHx, including:
    • Recent travel data, with city finder;
    • Current medications with drug lookup; and
    • Medical and surgical history with ICD-10 finder.
  • Add and edit assessments / physical exams.
  • Nearby fire hydrants list.
  • Fire preplan for the origin facility.
  • Interactive stroke screens including:
    • L.A.P.S.S.
    • Cincinnati
    • R.A.C.E.
    • E.M.S.A.

Launching the Offline PCR

Crew members can launch the Offline PCR right from AngelTrack, whenever they anticipate losing their internet connection.

To launch it, from any crew area of AngelTrack, crew members just click the SatelliteDish-1 Offline PCR icon, which appears in the top-right corner of the page.

During the first launch, all of the Offline PCR's files will be automatically downloaded to the crew member's mobile device. On subsequent launches, the files will be re-used, so that they need not be re-downloaded. AngelTrack automatically keeps these files updated when new versions become available, so there is no patching or other maintenance required.

Automatic launch

AngelTrack is willing to automatically launch the Offline PCR whenever a crew member clicks the "enroute" progress button in the online PCR from a mobile device. To enable this feature, crew members can click their initials to visit their Employee Self-Edit page, and find the setting on the "Customizations" tab.

Logging in to AngelTrack from the Offline PCR

When it launches, the Offline PCR will utilize the crew member's current login to AngelTrack, avoiding the need to re-login.

If the crew member logs out from AngelTrack in a different browser tab, the Offline PCR will also be logged-out. When that happens, the Offline PCR will display the login page, inviting the user to log back in again if desired.

Likewise if the crew puts the mobile device to sleep for many hours, such that their AngelTrack login expires. When it wakes up again, the Offline PCR will prompt the crew member to re-login; until that's done, the Offline PCR will keep any user-created data in the Outbox (see below for an explanation of the Outbox).

Using the Offline PCR's Navigation Bar

These are the meanings of the icons in the Offline PCR's navigation top-bar:

Icon Function

At last sync, the currently logged-in employee was off-duty.
TimeClockIcon.oncall.small At last sync, the currently logged-in employee was on-call.
TimeClockIcon.onduty.small At last sync, the currently logged-in employee was on-duty.
Upload.small-2 Visit the Outbox to view any user-created data that is queued.
Offline.small The mobile device is NOT connected to the internet, and so the Offline PCR cannot synchronize.
User-created data will queue up in the Outbox.
Online.small The mobile device is currently connected to the internet, and so the Offline PCR can synchronize normally.
Any user-created data queued in the Outbox will be automatically sent to the server.
GPSError.small The mobile device was unable to calculate a GPS position.
This occurs when a device has no GPS receiver, or when the user has (when prompted) forbidden AngelTrack to collect a GPS position.
GPSInaccurate.small The Offline PCR has received a fresh but inaccurate GPS position from the mobile device.
Minimum GPS position accuracy is configured under the Preferences page, under AngelTrack's Settings page.
GPSOkay.small The Offline PCR has received a fresh and accurate GPS position from the mobile device.
GPSWaiting.small The Offline PCR is waiting for the mobile device to calculate and return its GPS position.
Home.crew-1 Switch back to regular (online) AngelTrack, remaining logged-in.
Shortcut: ALT+C
Logout Close the Offline PCR and logout of AngelTrack.
Shortcut: ALT+X
TrafficLight.yellow Due to multiple open browser tabs, or intense recent activity, the Offline PCR's synchronizer has slowed down a bit.
All functionality is still available, but it will wait a bit longer between synchronizations.

Using the Offline PCR to Run a Call

It is easy to use the Offline PCR to run a call, because it is very similar to the regular (online) run-call pages.

Along its top-bar, any active assigned calls are shown as links, indicating the service requested and the patient's last name (if known). Whenever an assigned call is active, the Offline PCR automatically switches to the run-call page, same way that normal (online) AngelTrack does.

The run-call and signature-collection pages all look and act the same as their online versions. The only difference is, all user-created data -- such as time punches, odometer readings, collected signatures, and the like -- queues up in the Outbox, where it will be uploaded to the server whenever possible.

Easily switch back and forth from online PCR to Offline PCR

At any time during this process, as long as the Outbox has emptied itself out, the crew member can click the Home.crew crew-home icon to switch back to regular (online) AngelTrack, and perform the same functions there.

This will be necessary because the Offline PCR does not contain the full functionality of the online PCR. Thus, to finish up a report and submit it to QA, the crew member must eventually switch back to the online PCR.

Fortunately, switching back and forth requires only one click, with no need to re-login, and no need for a separate browser tab or window.

Understanding the Sync Process and the Outbox

All changes made by the crew member in the Offline PCR will queue up in its Outbox, where they await the opportunity for upload to the server.

Until that upload occurs, the AngelTrack server does not know about the changes. For example, if the crew member makes an "on scene" time punch, but doesn't have an internet connection, then the AngelTrack server does not know that he has arrived on-scene, and so the dispatch board will still show the crew as "enroute".

Furthermore, until that upload occurs, the data exists only in the crew member's browser, inside the Offline PCR web-app. If the user closes their browser abruptly, or reboots their device, the data could be lost before the Offline PCR has a chance to upload it to the server for safe keeping.

Thus it is important for the crew to get an internet connection whenever possible, so that user-created data can be sent up, and fresh call-status data can be pulled back down.

Must synchronize at least once an hour

Indeed, the Offline PCR expects to get a connection at least once an hour. If more than one hour passes without a successful synchronization, the Offline PCR will pause, and tell the user that a connection is required before any more user input will be accepted.

Monitoring the Outbox

The Upload.small-1 cloud icon always has a numeric indication next to it, showing how much user-created data is queued for upload. Click the icon to visit the Outbox and view the queue.

The Outbox also shows status and diagnostic information about recent synchronization attempts, in case there is a problem.