After you reach the vicinities of the comms tower in the Park Row district, locate the bandits staying on one of the big balconies. It is a good idea to sabotage, first, the guns of two of the enemies (disruptor) and stat fighting the pretty easy fights afterwards. Right after the fights, locate the grate of the venting shaft, jump inside and start squeezing through it.
Do not attempt to open the reinforced door straight away, because there is the electric current flowing through it. Select the remote control batarang from the inventory and turn left. Throw the batarang, make sure that it comes into contact with the discharges and direct it towards the nearby fuse box.
You may now open the reinforced door. Select the Cryptographic Sequencer from the inventory and solve the hacking minigame, to determine the password (the screenshot).