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I'm wondering if Bluetooth 4.0 (low-energy) mobile phones could discover classic Bluetooth devices (3.0 and lower), and vice-versa. All I am interested in is discovering the "friendly names".

EDIT: As I have understood the replies of this post, Bluetooth 4.0 can discover classic Bluetooth devices but not the other way around. Then my follow-up question is, can a Bluetooth 4.0 device in LE mode discover classic Bluetooth devices?

user3547137
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The answer depends on if you mean Bluetooth v4.0 device, or BLE device, the two are not the same.

Bluetooth v4.0 = Classic Bluetooth + Bluetooth High Speed + Bluetooth Low Energy

Therefore, Bluetooth Low Energy is only a subset of Bluetooth v4.0. If your question is regarding Bluetooth v4.0 phones (generally phones are not BLE only), then the answer is Yes, Bluetooth v4.0 mobile phones can theoretically discover Bluetooth v3.0 devices and lower.

Youssif Saeed
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Hate to be blunt, but nope not possible (although it would be handy). 4.0 is 4.0 alone. Check out the Bluetooth Core Spec for more info

Tommy Devoy
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  • I disagree. All BLE mobile devices I have seen also support classic/legacy Bluetooth. For example, my iPhone happily connects to my BT 2.1 car kits and headsets. You are right, though about the "vice-versa". A classic BT device has no visibility of BT 4.0 devices – Paulw11 Apr 17 '14 at 23:58
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    @Paulw11 You are right and tdevoy is right. BLE 4.0 devices only have visibility to other BLE 4.0 devices. However phones are dual mode devices, in the sense that they support both 2.1 and 4.0, allowing them to detect both. There a single mode 4.0 devices that would not be able to work with 2.1 devices, but those are normally not in phones. – Zomb Apr 18 '14 at 00:35
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No a BLE can not discover a classic bluetooth device nor a classic bluetooth device can discover a BLE.

A device with BT V4 will discover both. And A BT V4 will be discovered by BLE if it is advertising as BLE.

I also had same question, so I did little experiment. I may contribute to this topic from my experiment that I did with old mobile(Nokia C5-00), New mobile(Samsung galaxy grand prime) and two bluegiga ble113 chips.

I swithched on bluetooth of all the devices and started scanning for near by devices I observed the following:

Observation1: Samsung galaxy grand prime (BT version 4 +Ble): It was showing both bluegiga ble113 chips, and Nokia C5-00 on the list.

Observation2: Nokia C5-00 (Earlier version of BT): It was showing only Samsung galaxy grand prime in the list.

Observation3: ble113: Out of the two ble113 chips one was in advertising mode and other in scanning mode at first the scanner chip was discovering only other BLE113 advertiser chip, but when I started advertising from Samsung galaxy grand prime phone using BLEBroadcast app the ble scanner chip started discovering the Samsung galaxy grand prime phone also.

Vivek Singh
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  • Can you add a conclusion based on your observations that actually answers the second part of OPs question? – ophychius May 16 '17 at 04:59
  • The new mobiles have both Classic Bluetooth stack as well as Bluetooth Low Energy, they will discover the classic BT devices and ble in their vicinity. A Bluetooth LE powered device can not discover a classic Bluetooth device nor a classic Bluetooth device can discover a BLE. But Device with BT V4 will discover both while scanning (I think during Scanning the BT V4 device uses both BLe and BT classic protocols so they discover both but during advertising they work as either of the one. This is what I feel any correction or any comment will be appreciated). – Vivek Singh May 16 '17 at 06:11
  • I think I am correct see the link given:http://stackoverflow.com/questions/29176653/is-it-possible-and-does-it-make-sense-to-have-a-bluetooth-iot-device-in-periph?rq=1 – Vivek Singh May 16 '17 at 06:15
  • No a BLE can not discover a classic bluetooth device nor a classic bluetooth device can discover a BLE. – Vivek Singh May 16 '17 at 11:38
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Its perhaps late but just to clarify. The question in the title sounds like its asking about the interoperability of the two different Bluetooth modes, but the details of the question drift toward whether or not the mobile phone supports these two capabilities.

As far as the interoperability is concerned, as pointed out by VSingh, Classic Bluetooth discovery and Bluetooth Low Energy discovery work in opposite ways.

In classic, the endpoint [eg your Android] SEARCHING for devices TRANSMITS inquiry packets. Devices in discoverable mode, LISTEN for these packets and respond accordingly.

In Bluetooth Low energy, the endpoint [eg your Android] SEARCHING for devices LISTENS (scans) for advertisement packets. BTLE devices that are discoverable TRANSMIT these advertisement packets.

If the radio on your mobile device can do both of these things, then you can discover both classic and low energy devices.

Brian Reinhold
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