Question : Problem: E1 cards for Cisco 1841 Router

I need to buy E1 cards for an Cisco 1841 router. Which model should i buy?

Answer : Problem: E1 cards for Cisco 1841 Router

VWIC-1MFT-E1       1-port RJ-48 multiflex trunk-E1 data only
VWIC-2MFT-E1       2-port RJ-48 multiflex trunk-E1 data only
VWIC-2MFT-E1-DI       2-port RJ-48 multiflex trunk-E1 with drop and insert data only