 One of the first graphics based BBS applications was Excalibur BBS with a low bandwidth applications that required its own client for efficiency.
<fluency>  One of the first graphics based BBS applications was Excalibur BBS with a low bandwidth applications that required its own client for efficiency.
 One of the first graphics based BBS applications was Excalibur BBS with low-bandwidth applications that required its own client for efficiency.