EssentialFax will work with most common faxmodems (the dialup kind), but we have often found the following modems to be problematic:
Conexant SoftK56 modems
Conexant PCI CX11252-41Z Soft Modem
Motorola SM56 modems
Creative Modem Blaster modems
Intel HaM modems (and other modems of the HaM variety)
Lucent Win modems
LT Win modems
Ambient HaM modems
LSI USB 2.0 Soft Modems
Modems with mixed results:
PCI Soft Data Fax Modem with SmartCPThis modem is terrible for fax receiving. At this time we have no workaround. It works OK for sending faxes.
Conexant USB D400 (distributed with some DELL systems)This modem does not do well with fax receiving, although it works fine for fax sending. If the modem answers incoming calls, but fails to establish a fax session and ends with a Fatal Timeout Error - some customers report success using a transfer rate of 4800 for Item # 16 in Preferences.
Conexant D850 (several variations)This modem does not do well with fax sending, although it works fine for fax receiving.