I have just had my Optus modem replaced, it's a Sagemcom F@ST 5366 TN modem. I have been able to establish wifi connections in the house for the mobile phones and laptops but I have not had any success in establishing wifi connection for the Sony PlayStation 3 through the Sony smart tv. The wifi runs on a 5ghz frequency and I understand that the PlayStation may not be able to run on this frequency. The previous Sagemcom modem that I had, had both the 2.4ghz frequency and the 5.0ghz frequency, and I remember that when I tried to connect the wifi on the playstation (which is located downstairs, the modem is upstairs) that I could not connect to the 5.0ghz but only to the 2.4ghz frequency - this was also an issue most of the time when trying to use the wifi on the mobile phones in this room. Is there an issue in trying to use the 5.0ghz frequency for the Sony PlayStation 3? Is it possible that the current modem that I have can be configured for both frequencies like the previous modem?
You should be OK. Firmware version with suffix ending 105 shows two SSIDs when both radios are enabled within the Modems's Menu screens. Would expect suffix ending 125 to be the same?
Connect to the modem's 5Ghz SSID from a 5 Ghz device, log into to modem with printed label details, on Home Screen , select WiFi tile and Enable the 2.4 Ghz radio. Save/Apply and you should be able to see it from the PS3. I am using an iPhone 6, so my view may be different to yours.
Depending on when you got your PS3, you may be limited to 802.11 b/g 2.4 Ghz speeds only.