If you just connect an output of your 7404 chip to a BNC connector you don't have to worry about pull-ups or pull-downs on the output side. It looks like outputs of this chip cannot be tristated so you should always have a known output of the BNC connector. The output will be determined by the input of the NOT gate. 2SK125 Silicon N-Channel Junction FET Components datasheet pdf data sheet FREE from Datasheet4U.com Datasheet (data sheet) search for integrated circuits (ic), semiconductors and other electronic components such as resistors, capacitors, transistors and diodes.
7404 Tape and reel SN7404DR SOIC − D Tube SN74LS04D LS04 0°C to 70°C Tape and reel SN74LS04DR Tube SN74S04D S04 Tape and reel SN74S04DR Tape and reel SN7404NSR SN7404 SOP − NS Tape and reel SN74LS04NSR 74LS04 Tape and reel SN74S04NSR 74S04 SSOP − DB Tape and reel SN74LS04DBR LS04 Tube SN5404J SN5404J Tube SNJ5404J SNJ5404J CDIP − J AC125 Transistor Datasheet pdf, AC125 Equivalent. Parameters and Characteristics