Do I have to use the Telco port on a Grandstream gateway?

On the GXW4216, 4224 and 4232 it's optional — there are front RJ11 sockets too. On the GXW4248 it's mandatory; there are no front ports.

Does the gateway come with an RJ21 cable?

Only the GXW4248 includes one. For the smaller models you'll need to supply a male RJ21 Telco cable.

Can I use the same leaded panels as my Cisco gateways?

Generally yes — an RJ21-to-RJ11 leaded panel doesn't care which brand of gateway is feeding it, as long as the connector gender and port count match.

Why does my 48-port gateway have two connectors instead of one?

A single RJ21 carries 24 usable pairs, so 48 ports need two. The same logic applies to the 32-port GXW4232.

Grandstream Voice Gateway Wiring Guide

Grandstream's GXW42xx range is a popular, budget-friendly way to keep analogue phones and fax machines alive on a SIP network, and it turns up constantly in small-business and multi-tenant installs. Wiring one is straightforward once you understand how the ports are laid out — and that layout changes a little depending on which model you've got in front of you.

The range at a glance

The series runs in four sizes: the GXW4216 (16 ports), GXW4224 (24), GXW4232 (32) and GXW4248 (48). All of them are FXS gateways — analogue devices plug into them, and they bridge those devices onto your VoIP system. Where they differ, for cabling purposes, is how those ports come out of the box.

Model	FXS ports	Telco connectors	Tidy panel choice
GXW4216	16	1	24-way leaded panel
GXW4224	24	1	24-way leaded panel
GXW4232	32	2	48-way, or two panels
GXW4248	48	2	48-way, or two 24-way panels

The smaller units: front ports or Telco, your choice

On the GXW4216 and GXW4224, you get individual RJ11 sockets on the front for plugging phones in directly — handy when you've only a handful of lines. But each also has a 50-pin RJ21 Telco (Amphenol) port as an alternative. For anything beyond a few phones, that Telco port is the sensible route: one cable out to a leaded patch panel, and all your lines land in a tidy, labelled row rather than a tangle of individual leads. The 32-port GXW4232 works the same way but spreads its ports across two Telco connectors.

The GXW4248: Telco only

The 48-port GXW4248 is different. It has no individual front sockets at all — wiring is done entirely through two 50-pin Telco connectors on the rear, 24 ports each. So on this one it isn't optional: you're using RJ21 cables and panels whether you like it or not. Plan for two male RJ21 leads and either two 24-way leaded panels or a single 48-way.

Wiring it up

The Telco port on the gateway is female, so — exactly as with the Cisco units — you need a male RJ21 cable. Grandstream only includes a cable in the GXW4248 box; for the smaller models you'll supply your own. Connect the gateway to a leaded RJ11 patch panel and the ports map straight through in order.

One quirk worth knowing: on each RJ21 connector, the last pair (pins 25 and 50) isn't connected. Each 25-pair cable therefore carries 24 live ports — which is exactly why a 24-way panel pairs so neatly with one connector. If a port count ever looks one short, that's the reason; it's by design, not a fault.

Matching the panel to the model

For a GXW4216 or GXW4224, one 24-way leaded panel covers the single Telco connector with room to spare. The GXW4232 and GXW4248 both use two connectors, so size up to a 48-way panel or run two smaller panels — whichever fits your rack layout better.

Frequently asked questions

Wiring a Grandstream install? Browse leaded patch panels and male RJ21 Telco cables in 24-way and 48-way. Custom lengths and bespoke pin-outs made to order in the UK — send us your spec.