Cisco Cisco IOS Software Release 12.4(23)

WIC-1SHDSL-V3: One-port G.SHDSL WIC with 4-wire support.

WIC-1AM: One-port analog modem. 

WIC-2AM: Two-port analog modem. 

HWIC-4A/S: Four low-speed synchronous/asynchronous serial ports.

HWIC-4ESW: Four-port 10/100 Ethernet switch interface card.

HWIC-4T: Four-port serial high-speed WAN interface card.

HWIC-8A/S-232: Eight low-speed synchronous/asynchronous serial ports, EIA-232 only.

HWIC-8A: Eight asynchronous EIA-232 serial ports.

HWIC-16A: Sixteen-port asynchronous high-speed WAN interface card, EIA-232 only.

The following T1/E1 Multiflex Voice/WAN interface cards (VWICs) are also supported on the 
Cisco 1841 for data applications only:

VWIC-1MFT-E1: One-port RJ-48 multiflex trunk (E1). 

VWIC-2MFT-E1: Two-port RJ-48 multiflex trunk (E1). 

VWIC-1MFT-G703: One-port RJ-48 multiflex trunk (G.703). 

VWIC-2MFT-G703: Two-port RJ-48 multiflex trunk (G.703). 

VWIC-1MFT-T1: One-port RJ-48 multiflex trunk (T1). 

VWIC-2MFT-T1: Two-port RJ-48 multiflex trunk (T1). 

VWIC-2MFT-E1-DI: Two-port RJ-48 multiflex trunk (E1) (with Drop and Insert). 

VWIC-2MFT-T1-DI: Two-port RJ-48 multiflex trunk (T1) (with Drop and Insert). 

The AIM-VPN/BPII-PLUS: DES/3DES/AES VPN Encryption/Compression card is also supported on 
the Cisco 1841.

For feature support in Cisco IOS Release 12.4, see the