Cisco offers the carrying card with two 56K 12-port modules installed.The 56K 12-port module uses Rockwell's K56Flex technology. The module can send data at up to 56 kbps and receive data at up to 33.6 kbps. Connections at 56 kbps start as analog, are converted to digital, and are not converted back to analog at the service provider. Because one conversion (from digital to analog) is omitted, speeds of up to 56 kbps are possible. However, the actual speed that you can achieve with the module depends on the condition of your local telephone network.