TP-Link TL-MR3420 User Manual page 48

 Disable Security - If you do not want to use wireless security, select this check box, but it's
strongly recommended to choose one of the following modes to enable security.
 WPA/WPA2 – Personal (Recommended) - It's the WPA/WPA2 authentication type
based on pre-shared passphrase.
 Version - you can choose the version of the WPA-Personal security on the drop-down
list. The default setting is Automatic, which can select WPA-Personal (Pre-shared key
of WPA) or WPA2-Personal (Pre-shared key of WPA) automatically based on the
wireless station's capability and request.
 Encryption - When WPA-Personal or WPA is set as the Authentication Type, you can
select either Automatic, or TKIP or AES as Encryption.

Note:
If you check the WPA/WPA2 – Personal (Recommended)
encryption, you will find a notice in red as shown in Figure 4-22.
TL-MR3420 3G/4G Wireless N Router User Guide
Figure 4-21
radio button and choose TKIP
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