Lock a table in Sybase ASE 15.5

I would like to lock a table to only allow users to perform read operation in Sybase ASE 15.5, how can I do it? I have tried the below command, but seems there is some confusion. Any idea? Session A: Perform below commands and after that try to perform insert operation. New records can still insert into locked table (but I think it is not commit the transaction yet). Can still select record from the locked table. begin transaction lock table testB in share mode Session B: Cannot select data from the locked table.