Central standard time I'm guessing, so mid-US I guess "central" and "standard" mean here, so I'm guesstimating GMT-7. That would put it around 8:30 GMT.
While I know what you meant in the parent, "numeric timezone" isn't a thing. When it's in a numeric format the correct term is "offset". It cannot be referred to as a timezone as it's timezone will remain constant, but offset may change depending on the time of year (and the impact daylight savings has on the correct offset).
For what it's worth, i too hate when people say things like "EST","CST" etc. Not only are they difficult to remember, but they're ambiguous. i.e. AEST is Australian Eastern Standard Time, but no one includes the A when it's spoken and rarely when its written, which often means when two people over email say "lets talk at 9am EST", hopefully they're on the same continent, or they will miss each other by around ~14 hours.
Well that's some interesting pedantry, but I think it was fairly clear what they meant, and I was sighing along with them when I had no idea what time the answer actually referred to.
You're too lazy to look up the start time so you ask some one to tell you, then when they tell you, you're too lazy to convert the time zone they used. You're acting like a child. Use Google if it's so damn inconvenient for you.
You're an adult with the Internet right in front of you, act like it.
[0] https://www.google.com/search?q=1%3A30+cst
[1] https://twitter.com/jeff_foust/status/780835809696092161
[2] https://twitter.com/elonmusk/status/780838839644483586