gammu-smsd-tables(7) on Linux
The text e8cc35ad81fe, as Debian 7 (Wheezy) shipped it.
description of tables for database backends of gammu-smsd(1) The backends themselves are described in their sections, this document describes general database structure and required tables. More SMS daemons can share single database. If you do not specify PhoneID in their configuration, all are treated equally and you have no guarantee which one sends outgoing message. If you configure PhoneID and use it when inserting message to the outbox table (gammu-smsd-inject does this), each SMS daemon will have separate outbox queue.