Use B-538-AS when you would like to extend the channels of GL800. The following diagram shows you the connection.
| 20 ch | 40 ch | 100 ch | 200 ch |
| GL800 | One | One | One | One |
| Expansion terminal base kit (B-537) | - | One | One | One |
20-channel expansion terminal set
(B-538) | - | One | Four | Nine |
