The GBX20 is a backlit LCD extension module supported by the GXV3350 and GRP2615. The module includes 20 dual-colored extension keys and 2 arrow keys for page switching (allowing each GBX20 to support up to 40 contacts/extensions.). Connect up to 4 GBX20 modules to compatible Grandstream phones for a total of 160 contacts/extensions.
| Technical details | |
| Phonebook capacity: | 40 entries |
| Wall mountable: |  |
| Caller ID: |  |
| Package weight: | 700 g |
| Colour | |
| Product colour: | Grey |
| Weight & dimensions | |
| Depth: | 33.5 mm |
| Width: | 124 mm |
| Height: | 210 mm |
| Weight: | 360 g |
