Many people are using dual-SIM mobile for a variety of reasons. A common problem observed is the continuity of connectivity of call during communication. Disconnectivity of call affects the market share of an operator. This paper suggests a model based on markov chain to check the relationship between call transitions and call attempts over SIM S1 and SIM S2 when congestion and disconnectivity parameter is high or low to complete the call. The assessment reveals that the transitions over SIMs vary at different attempt. Fig 1-4 reveals that the user tries to connect S1 and S2 till attempt 5. Fig 5-8 reveals that the user try to connect SIM S1 till attempt 6 and SIM S2 till attempt 8. When p (high), pL (high), c1 (low), c2 (high) and d1 (high), and when p (low), pL (low), c1 (low), c2 (low), d2 (high), the transition value is very high at attempt 2 over SIM S1 and SIM S2. The graphical Study express the relationship between call transitions and attempts based on Markov chain using Excel tools with varying parameter values.