Avaya 6400 Series Telephones Avaya 6400 Series Telephones Showing all 3 results Sort by popularity Sort by average rating Sort by latest Sort by price: low to high Sort by price: high to low Avaya 6408D+ $35.00 – $80.00 Select optionsQuick View Avaya XM24 24-Button Expansion Module $45.00 – $75.00 Select optionsQuick View Avaya 6416D+M Digital Telephone $45.00 – $65.00 Select optionsQuick View