Federal Tax Payment for Form 1040 - Can I file via EFTPS?

[optionsguy]

- I have a sole proprietorship side project in addition to my regular job
- I file quarterly tax payments every quarter
- My CPA just filed my taxes, now I have to make my federal payment for what I still owe in 2014 (never made a Q4 payment).
- Can I file this regular Form 1040 payment via EFTPS? Or do I need to do it somewhere else?

[optionsguy]

And more broadly - what's the difference between EFTPS and the IRS "direct pay"? Why are there two systems?