Acer Aspire 4310 Service Manual page 115

Modem-Related Symptoms
Symptom / Error
Internal modem does not work correctly.
NOTE: If you cannot find a symptom or an error in this list and the problem remains, see "Undetermined
Problems" on page 107.
Chapter 4
Check or do the following in sequence
Modem phone port
Modem combo board
Mainboard
105