Handbook:Advanced Server Configuration:Modem Groups
Groups of modems can be referenced by name using a facility termed modem groups. A modem group defines a logical name for a set of modem devices on a server. This name can be used by clients in the same way that a specific modem device is used. The default modem to use for outbound jobs, "any", is actually just a predefined modem group. Modem groups are useful for groups that want to logically partition a set of modems on a single server.
Modem groups are defined with the ModemGroup configuration parameter. Each definition specifies a name and a regular expression that identifies the set of modems that are to be included in the group. For example,
is the builtin definition for "any". Regular expressions are matched against device identifiers for modems that are signalled to faxq by faxmodem or faxgetty.
Users of older versions of HylaFAX may see references to a modem class instead of group (ModemClass). The confusion between modem classes (ie: logical groups of modems) and the fax class that modem was operating in (ie: Class 1, Class 2) led to a renaming of this facility to the more intuitive ModemGroup.