What station in New England has the longest continuing call letters and COL on the same frequency that only changed by treaty mandates?

[Kevin Vahey]

What station in New England has the longest continuing call letters
and COL on the same frequency that only changed by treaty mandates?

I am thinking of WTIC in Hartford (1925) - WBZ was Springfield until
1931 - Boston was WBZA and then they flipped calls.

WEEI has had active call letters in Boston since 1924 but.....

On FM I lean towards WTIC-FM Hartford (1944) - Boston it would be WERS (1949)