A phone that does not ring inside a Faraday bag gives you one observation about one attempted connection. It doesn’t prove that every wireless function is isolated in every setting. To check a bag usefully, start with what you need it to block, check how the device fits, and define how you’ll evaluate the results. That makes the check relevant to the job instead of a reassuring demonstration with unclear limits.
We manufacture RF shielding bags in multiple sizes and can accommodate custom-size requests. When choosing a bag from JEMIC, tell us which devices it will hold and how it will be used. The bag must allow its closure to be secured as intended with the actual load inside. A device that fits through the opening may not fit once its case and accessories are included.
Define the Connection You Are Checking
Write down the relevant functions before starting. A cellular-call check does not answer the same question as a Wi-Fi or Bluetooth check. The device settings and network involved also belong in the record. If the phone is using Wi-Fi calling, for example, the phone call label alone does not identify the connection being evaluated.
Separate a functional screening check from measured shielding performance. A screening check can reveal an obvious problem and help assess a defined use condition. It does not produce an attenuation rating or establish coverage of frequencies that were not tested. Where the consequences of an undetected connection are significant, the security or technical lead should set a validation plan with appropriate RF expertise.
Inspect the Bag Before Testing It
Check the lining, seams, and closure for damage or contamination, and follow the instructions for that bag. Check that the intended device arrangement leaves the closure unobstructed. Do not run a charging cable through an ordinary opening and assume isolation remains unchanged; design and evaluate a cable arrangement for that purpose. An improvised cable path makes the closed-bag check a different configuration.
- Use a separate, authorized test device. Do not experiment on a seized phone or change an evidence device’s settings to demonstrate that a bag works.
- Establish a working connection outside the bag first, using the function you intend to check. A failed outside connection makes the bag result inconclusive.
- Place the device in the intended position, secure the closure as instructed, and attempt the defined connection. Record what occurred rather than writing a general all-signals-blocked conclusion.
- Evaluate other required functions separately under the approved plan. Keep the bag, device, settings, location, and date identifiable so a later check can be compared.
- Confirm the test device can connect again outside the bag. Investigate inconsistent results rather than repeating the check until one attempt appears successful.
Treat these steps as a way to organize a limited operational check, not as a forensic procedure or a laboratory certification method. Evidence-handling organizations must use their own approved procedures. For routine workplace use, the same discipline still helps: staff should know which bag was checked and what the result actually covered.
| Observed result | Reasonable interpretation |
| The device cannot connect outside the bag | The screening check has no working baseline. |
| It connects outside but not during the closed-bag attempt | That attempted connection was not completed under those conditions. |
| A required connection succeeds inside | Stop relying on that configuration for the required isolation and investigate. |
| Results change between attempts | The cause remains unresolved; do not label the bag verified from the favorable attempt. |
Do Not Turn a Limited Result Into a Broad Promise
Consider a hypothetical facilities team checking bags for company phones before a restricted meeting. A phone receives a call outside the bag and does not ring after the closure is secured. The team has useful screening information about that attempt. If the policy also requires Wi-Fi isolation, however, the call result does not complete the check. The missing function needs its own evaluation, and the policy owner decides what evidence is sufficient for use.
If a required connection succeeds, set the bag aside from that use and inspect the closure, loading, and condition. Record the failure and any correction before another evaluation. A changed device, damaged lining, or new cable arrangement may require a fresh review. Inspection frequency should reflect use and consequence, not an arbitrary promise that every bag remains effective for the same interval.
Choose a Bag and Verification Plan Together
A missed call doesn’t complete the check when the job also requires Wi-Fi or Bluetooth isolation. For the restricted-meeting example, you still need to evaluate each required function under the approved plan. If a required connection succeeds, stop relying on that bag configuration until the cause is resolved and it has been reevaluated. When an undetected connection could compromise sensitive information or evidence, have the responsible technical lead define the necessary validation instead of treating a simple call attempt as proof of universal isolation.
Contact JEMIC at (717) 232-1030 to discuss your device dimensions, number of devices, and bag requirements. We can discuss our available sizes and custom-size options so you can select a configuration to evaluate for your application.
