Service manual

C-22 AlphaServer 4000/4100 Service Manual
C.1.7 Modem Dialog Details
This section provides further details on the dialog between the RCM and the
modem and is intended to help you reprogram your modem if necessary.
Phases of Modem Operation
The RCM is programmed to expect specific responses from the modem during four
phases of operation:
• Initialization
• Ring detection
• Answer
• Hang-up
The initialization and answer command strings are stored in the RCM NVRAM. The
factory default strings are:
Initialization string: AT&F0EVS0=0S12=50<cr>
Answer string ATXA<cr>
NOTE: All modem commands must be terminated with a <cr> character (0x0d
hex).
Initialization
The RCM initializes the modem to the following configuration:
Factory defaults (&F0)
No Echo (E)
Numeric response codes (V)
No Auto Answer (S0=0)
Guard-band = 1 second (S12=50)
Fixed modem-to-RCM baud rate
Connect at highest possible reliability and speed
The RCM expects to receive a “0<cr>” (OK) in response to the initialization string.
If it does not, the enable command will fail.