Huawei has released various sub-models of B593 WiFi routers in various countries. Recently, B593s-931 (also known as B593-931) also gone for sell in the Philippines with Globe Tattoo and Smart Telecoms.
Globe Tatoo has un-customized firmware and after changing the default SIM, it asks for unlock code (get unlock code). But, Smart Bro does not ask for unlock code, as it comes with customized firmware. You may also get the device from Sun Broadband.
If you have also customized firmware router Huawei B593s-931, then you can not unlock it without flashing the device.
Download un-customized firmware of Huawei B593s-931 and follow the rest of procedures from this link. After flashing or changing the firmware, you will get the unlocking screen as the above mentioned image. Put the correct unlock / NCK code and enjoy the unlocked B593s-931 with any carrier SIM.
Sub sub-models listing:
HUAWEI B593u-12: FDD DD800/900/1800/2100/2600MHz
HUAWEI B593s-22: FDD DD800/900/1800/2100/2600MHz & TDD 2600MHz
HUAWEI B593s-82: FDD DD800/1800/2600MHz & TDD 2300/2600MHz
HUAWEI B593u-91: TDD 2300/2600MHz
HUAWEI B593s-601: FDD 1800/2600MHz & TDD 2300MHz
HUAWEI B593s-58: TDD 1900/2300/2600MHz
HUAWEI B593s-58b: TDD 1900/2300MHz
HUAWEI B593s-42: TDD 3500MHz