When two-port networks are interconnected:
Series Connection: The overall Z-parameters (Impedance parameters) are the sum of individual Z-parameters. \( [Z_{total}] = [Z_A] + [Z_B] \).
Parallel Connection: The overall Y-parameters (Admittance parameters) are the sum of individual Y-parameters.
Cascade Connection: The overall ABCD-parameters (Transmission parameters) matrices are multiplied.
Series-Parallel Connection: The overall H-parameters (Hybrid parameters) are added.
For a series connection, Z parameters are added.
\[ \boxed{\text{Z parameters are added}} \]