Grandstream GBX20 Extension Module

The Grandstream GBX20 is an extension module: a panel of keys with its own 272 × 480 LCD that sits beside a desk phone and shows 40 colleagues, lines or shortcuts per module.

Busy lamp field is the reason it exists. A receptionist needs to see, at a glance, who is on a call and who is free — and then transfer to them with one press rather than asking the caller to hold while they find out. Without it, every transfer is a guess. With four modules the phone shows up to 160 contacts, which covers a large organisation from one desk.

Because the labels are on a screen rather than a paper insert, they update themselves when the phone system changes. Nobody has to reprint anything when somebody joins or leaves.

It fits the GRP2615, GRP2624, GRP2650 and GRP2670 desk phones and the GXV3350 and GXV3450 video phones. Check your model before ordering — not every phone accepts a module.

Key features

• 40 contacts per module, up to 160 with four modules
• 272 × 480 LCD — labels update from the phone system, no paper inserts
• Busy lamp field — see who is on a call before transferring
• Call park and pick-up
• Speed dial and presence
• Intercom
• Transfer and forward from the module

Works with

• GXV3450 — supported video phone
• GXP2200EXT — the module for GXP2140, GXP2170 and GXV3240
• Grandstream IP phones — check which models accept a module
• Grandstream UCM IP PBX range — the system that feeds the presence information
• All PSUs and accessories

Frequently asked questions

Which phones does it fit?

The GRP2615, GRP2624, GRP2650 and GRP2670 desk phones, and the GXV3350 and GXV3450 video phones. Not every Grandstream phone accepts a module — send us your model number and we will confirm before you order.

What does busy lamp field actually do?

It shows the state of other extensions: free, ringing, or on a call. A receptionist can see that before transferring, so the caller is not put through to a phone that is already engaged. It is the single biggest time-saver on a reception desk.

Do I need more than one?

Forty contacts covers most reception desks. Beyond that you can add up to four modules for 160. Bear in mind that a wall of keys nobody can find anything on is worse than a shorter list — group them sensibly.

Do the labels need reprinting when staff change?

No — that is the advantage of the LCD. Labels come from the phone system, so they follow a change of staff without anyone touching the desk.

Does it need its own power supply?

Modules draw from the phone, so a phone carrying several has less headroom on PoE. If a desk with modules is misbehaving, mains power for the phone is the first thing to try.

Does the phone system need to support it?

Presence and BLF come from the PBX, so yes — it needs to publish that information. It works as intended on a Grandstream UCM and on most standards-based systems.

Setting up a reception desk? Call 0333 242 1314 or email sales@clisecure.com — tell us the phone model and how many extensions need watching.