Secondary brokers also called as Sql brokers.
Am i wrong
Yes.
A database is opened in multi-user mode by the primary broker. It may or may not also be a connection broker that can spawn remote servers. This is determined by the -ServerType parameter. Any broker that is started against the database after the primary broker is a secondary broker. It too spawns servers, which may be 4GL, SQL, or both, depending on the -ServerType value. A secondary broker must be started with the -m3 parameter; that distinguishes it as a secondary.
You could, for example, start a database with a single SQL broker, e.g.:
proserve sports -ServerType SQL -S 12345
This would be a database with a SQL broker and no secondaries. Another example:
proserve sports -ServerType SQL -S 12345
proserve sports -ServerType 4GL -S 23456 -m3
This database has a primary broker that is also a SQL connection broker, and a secondary 4GL connection broker. So a broker can be primary or secondary independent of being 4GL or SQL (or other).