がわSS えすえす利用 りよう しゃだったら
kikogawa esue suri yōshadattara

Noun
Da Copula

The "-tara" conditional form ("if/when…") of 着呼側SS利用者

1. If/When [someone] is a user of the Support Side SS.; If [someone] were a Support Side SS user.

Tara Conditional
Computing