When was the television introduced to the public?
WRGB claims to be the world's oldest television station, tracing its roots to an experimental station founded on January 13, 1928, broadcasting from the General Electric factory in Schenectady, NY, under the call letters W2XB. It was popularly known as "WGY Television" after its sister radio station. Later in 1928, General Electric started a second facility, this one in New York City, which had the call letters W2XBS and which today is known as WNBC. The two stations were experimental in nature and had no regular programming, as receivers were operated by engineers within the company. The image of a Felix the Cat doll rotating on a turntable was broadcast for 2 hours every day for several years as new technology was being tested by the engineers.
When was the television introduced to the public on an experimental basis?
1928
History of television
The first official, paid advertising to appear on American commercial television occurred on the afternoon of July 1, 1941, over New York 
When was television introduced to the public with regular commercial telecasts?
1941
History of television
History of television
https://en.wikipedia.org/wiki/History%20of%20television
Timeline of the introduction of television in countries
https://en.wikipedia.org/wiki/Timeline%20of%20the%20introduction%20of%20television%20in%20countries
In the U.S., the Federal Communications Commission (FCC) allowed stations to broadcast advertisements beginning in July 1941, but required public service programming commitments as a requirement for a license.
History of television United States
WRGB claims to be the world's oldest television station, tracing its roots to an experimental station founded on January 13, 1928, broadcasting from the General Electric factory in Schenectady, NY, under the call letters W2XB. In the U.S., the Federal Communications Commission (FCC) allowed stations to broadcast advertisements beginning in July 1941, but required public service programming commitments as a requirement for a license.