إِنْ وَصَلْتَ فَاتَّصِلْ بِي.
Translation: If you arrive, call me.
The response is an imperative, ittiṣil, preceded by obligatory fāʾ. An imperative is not a jussive imperfect.
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Obligatory Fāʾ: Request-Type Response
The Jussive Imperfect: Governors, Conditions, and Request Responses
إِنْ وَصَلْتَ فَاتَّصِلْ بِي.
Translation: If you arrive, call me.
The response is an imperative, ittiṣil, preceded by obligatory fāʾ. An imperative is not a jussive imperfect.