Grandstream GXW4502 E1/T1/J1 Digital VoIP Gateway

The Grandstream GXW4502 is a digital VoIP gateway with two software-configurable E1/T1/J1 spans, converting up to 60 concurrent calls between digital ISDN trunks and SIP.

Bridge equipment for the middle of a migration. A legacy PBX that still speaks ISDN connects on one side; SIP trunks or a new SIP platform on the other. The gateway carries calls between the two, so the PBX replacement and the trunk migration stop being one terrifying weekend and become two separate projects on sensible timescales.

Two spans is the size for a site that ran a pair of ISDN30 circuits — sixty channels of legacy calling. One span is the GXW4501; four is the GXW4504. Count the spans on the old estate, not the number of buildings.

Key features

• 2 × E1/T1/J1 spans, software configurable — no hardware change between standards
• Up to 60 concurrent calls — two full E1s' worth of channels
• Digital-to-SIP in both directions — old PBX to new trunks, or new platform to old PBX
• Gigabit Ethernet with integrated NAT router — sits inline where needed
• TLS and SRTP — the SIP side is encrypted even though the ISDN side never was
• Remote provisioning and management — administered without a site visit

Works with

• Grandstream GXW4501 — one span, 30 calls
• Grandstream GXW4504 — four spans, 120 calls
• Grandstream UCM6304A — the SIP platform on the new side
• Grandstream HT881 — the analogue equivalent, for POTS lines rather than ISDN
• All Grandstream gateways

Frequently asked questions

Which direction does it convert?

Both — SIP on the IP side, E1/T1/J1 on the digital side. It serves an old PBX on new trunks just as well as a new platform reaching an old PBX.

Do I need two spans or one?

Count the circuits on the legacy side. Each E1 is 30 channels — a site that ran two ISDN30s needs both spans of this unit; a single circuit only needs the GXW4501.

E1, T1 or J1 — which do I have?

In the UK, E1. The spans are software configurable across all three standards, so the same hardware works internationally.

Is this a long-term or interim purchase?

Usually interim — but interim in telecoms often means years, and the box is built accordingly. It exists so neither the PBX nor the trunks force the other's timetable.

Does it work with non-Grandstream PBXs?

Yes — both sides are standards-based. Tell us what the old PBX is and we will confirm the signalling before you order.

Two ISDN circuits and a deadline? Call 0333 242 1314 or email sales@clisecure.com and we will map the migration before anything gets ceased.