subscriber trunk dialling

25 LETTERS · STARTS WITH S

subscriber trunk dialling is a valid 25-letter word worth 35 points in Scrabble and 45 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

S1U1B3S1C3R1I1B3E1R1T1R1U1N1K5D2I1A1L1L1I1N1G2

1 + 1 + 3 + 1 + 3 + 1 + 1 + 3 + 1 + 1 + 0 + 1 + 1 + 1 + 1 + 5 + 0 + 2 + 1 + 1 + 1 + 1 + 1 + 1 + 2 =35 PTS

DOUBLE WORD → 70TRIPLE WORD → 105

MEANING

What does subscriber trunk dialling mean?