в какой области начинается номер с +121...

Поздравляю! Эта область называется "Североамериканский план нумерации" :-))

+1 210: Texas (San Antonio metropolitan area)
Created by split from 512 in 1992.
Three-way split in 1997 created 830 and 956.

+1 211: Community Services Hotline (e.g., crisis line, United Way, etc.)

+1 212: New York City (Manhattan except for Marble Hill)
Split in 1984 to create 718.
Overlain by 917 in 1992 and by 646 in 1999.

+1 213: California (Downtown Los Angeles)
Originally covered the southern third of California; split to create 714 (1951), 805 (1957), 818 (1984), 310 (1991), 323 (1998), and 424 (2006).

+1 214: Texas (Dallas–Fort Worth metroplex)
Split to create 817 (1953), 903 (1990) and 972 (1996).
214 and 972 were merged and overlain with 469 in 1999.

+1 215: Pennsylvania (Philadelphia area including its suburbs in eastern Montgomery County and most of Bucks County as well as a very small portion of Berks County around the Hereford area, which is served by the Pennsburg 679 exchange.
Split to create 610 in 1994.
Overlain by 267 in 1997; a further overlay with 445 was proposed, but never implemented.

+1 216: Ohio (Cleveland area)
Three-way split in 1997 created 330 and 440.

+1 217: Illinois (Springfield, Champaign, Decatur, Urbana, Lincoln, and parts of central Illinois)
Split in 1957 to create part of 309.

+1 218: Minnesota (Duluth, Moorhead, Thief River Falls, Bemidji, Brainerd, International Falls, and most of northern Minnesota)
Split in 1954 to create 507.

+1 219: Indiana (northwest: Gary, Chesterton, Crown Point, East Chicago, Hammond, Hobart, Merrillville, Michigan City, Portage, Valparaiso)

Хотя звонить могли и через Интернет...