FINAL CHEAPEST CONCLUSION (see the very end)
Keep your existing DECT handsets by replacing the base station with a SIP-compatible model like the Gigaset N300IP FOR ABOUT £45
This is assuming the existing DECT base is analog only, no sip.
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Short cuts to sites
https://store.ui.com/us/en/category/managed-voip
https://www.gigaset.com/pro/en_en/cms/home/fusion.html
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EXAMPLE
Gigaset Fusion FX800W Pro Bundle (Inc 2 x SL800H Handsets) £386 (ex vat)
https://www.pmctelecom.co.uk/gigaset-fusion-fx800w-pro-bundle-inc-2-x-sl800h-handsets/
5 Inch 720p Touch and Swipe Display with Intuitive User Interface
Mini PBX with up to 20 Users and Integrated DECT Base Station
Up to 6 Simultaneous Calls (Max 4 DECT Calls)
Access to Google and Microsoft 365 Contacts
Headset Connection Via Bluetooth or USB-C
Flexible Connection Options
5 Local Answering Machines, Integrated Gigaset Smart Home Base Includes 2x Gigaset SL800H PRO DECT Handsets
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HEADS UP - While analogue is still available to use it with the above will require one of these, which is £70 ex vat.
The trouble is that as soon as BT switch off analogue, it is useless.
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My preliminary thinking is As we know BT is soon to disable all analog phones. For many years I have used the Siemens DX 800 A and the modern version of this is the ⚙️ Gigaset Fusion (FX800W PRO) which I am inclined to suggest to buy now as it will directly replace existing phones, I am guessing it still does analog but it also does everything else. Of course we need to check the market for whether there’s anything more suitable (see below). Basically, I’m looking for a system that will do what we already have in direct replacement of our existing phones while at the same time allowing us to apply all the new technologies that are available so there will be no interruption in incoming phone line service, crucial for uninterrupted sales. This device runs off POE so is of course also network connected. Right now, I’m thinking just go and buy a book we/youshould really check what else is out there.Price will be 500 quid or so. In terms of useful life as I say I’ve had mine for 20 years and it still works fine but of course it is obsolete these days.
And all this said we should look at what Unify has to offer, for which see below.
Initial search response
For a home office where you want top-of-the-line telephony, combining professional-grade features, reliability, and modern integration—Gigaset Fusion FX800W PRO is your ideal all-in-one Siemens (Gigaset) successor.
⸻
🥇 Top Recommendation: Gigaset Fusion FX800W PRO
🎯 Why It’s the Flagship:
| Feature | Description |
|---|---|
| Hybrid System | Combines IP desktop phone, DECT base station, mini PBX, and smart-home controller—all in one |
| Built-in DECT | Connect up to 8 Gigaset PRO handsets |
| Integrated VoIP PBX | Full-featured call routing, voicemail, group ring, internal calling, SIP trunk support |
| Modern Display | 5” capacitive colour touchscreen with intuitive UI |
| Secure VoIP | SIP over TLS and SRTP encryption supported |
| Business-ready | Includes directory sync, provisioning (TR-069), and VPN integration (OpenVPN) |
| Flexible Expansion | Works with N670/N870 multicell if roaming needed later |
| Smart Home Hub | Optional: Controls Zigbee or DECT-ULE home devices |
| No PC Required | Web-based admin interface and onboard configuration wizard |
| Design | Premium materials, tactile keyboard, status LEDs—designed to look professional in your home workspace |
🔗 Product site (Gigaset)
⸻
⚙️ Add-Ons (Optional):
• SL800H PRO or R700H PRO: Choose compact or rugged DECT handsets
• Gigaset N870 IP PRO: For multi-cell roaming in large homes or outbuildings
• Gigaset T440/T640 PRO: Expand into receptionist-style setups if needed later
• Gigaset E720A: For elderly family members, voice-assisted DECT with SOS⸻
🧠 Alternative Considerations (If You Want Options)
| Brand | Model | Why Consider It? |
|---|---|---|
| Yealink | T58A + W90 DECT | Android-based, video calls, top SIP support |
| Grandstream | GXV3380 + DP752 | Android + DECT, unified communication focus |
| Snom | M900 Multicell + D865 | German-made, secure, robust for prosumers |
However, none of these match the Fusion FX800W PRO in combining PBX, DECT, IP desk phone, and smart-home in one sleek unit.
⸻
💰 Price & Availability (as of 2025)
• RRP: ~€595 (device only) or ~€740+ with 2 SL800H PRO handsets
• Where to buy: Gigaset direct, Amazon EU, telecom specialists⸻
✅ Summary: Why It’s Best for Home Office
• All-in-one: Desktop phone, DECT base, PBX, and smart home in a single device
• Professional-quality VoIP: Easily connect to SIP providers or a cloud PBX
• Scalable: Add handsets or upgrade to multi-cell later if needed
• Future-proof: Encrypted comms, remote config, firmware updates
• No monthly fees: You own the system, not a service lease⸻
AND VERSUS UNIFY
The Gigaset Fusion FX800W PRO and Ubiquiti UniFi Talk platforms both aim to serve small offices and home professionals—but they differ fundamentally in design philosophy, deployment model, and ownership model.
Here’s a detailed comparison to help you choose:
⸻
🥊 Gigaset Fusion FX800W PRO vs Ubiquiti UniFi Talk
| Feature Category | Gigaset Fusion FX800W PRO | UniFi Talk (Ubiquiti) |
|---|---|---|
| Platform Type | All-in-one hardware PBX, DECT base, IP phone | Cloud-managed VoIP system with UniFi integration |
| Ownership Model | Self-hosted: Buy once, no mandatory cloud | Subscription-based: Monthly fee per line (e.g. $9.99/mo/number) |
| Call Routing / PBX | Built-in local PBX, no cloud dependency | Cloud PBX via UniFi Controller |
| Handset Support | Up to 8 DECT handsets (e.g. SL800H PRO) + 1 desk phone | UniFi Talk IP phones (Touch Max/Touch) over PoE; no DECT |
| Line Types Supported | SIP VoIP only, with or without internet | VoIP via UniFi Talk service or third-party SIP (limited) |
| Secure Communication | SIP over TLS, SRTP, local firewall control | Encrypted SIP via cloud controller (no offline mode) |
| Smartphone / App Support | None directly; DECT only | Yes, via UniFi Talk mobile app (iOS/Android) |
| Admin Interface | On-device & web GUI (no cloud needed) | UniFi Controller (cloud/web) |
| Local Failover / Power Cuts | Continues working if SIP is on LAN | Dependent on cloud access & UniFi gateway for SIP routing |
| Network Architecture | Ethernet or Wi-Fi + DECT radio built in | Requires UniFi OS Console (Dream Machine, Cloud Key) + PoE switch |
| Licensing | No recurring fees (SIP trunk optional) | Monthly per number ($9.99/mo per US number via Ubiquiti) |
| Smart Home Integration | Optional (DECT-ULE or Zigbee) | None |
⸻
🔍 Key Differentiators
✅ Gigaset Fusion FX800W PRO:
• Ideal for hybrid environments (analog + DECT + SIP)
• Works offline or online; no reliance on external cloud servers
• You own the PBX, SIP credentials, data, and hardware
• Especially suited for ISDN replacements, remote cottages, or privacy-sensitive users
• Great if you want to connect to any VoIP provider (e.g. Sipgate, Voipfone, Localphone)✅ UniFi Talk:
• Plug-and-play, fully cloud-managed
• Native mobile apps and call transfer across devices
• Tightly integrated with the UniFi ecosystem (perfect if you use Dream Machine SE, Cloud Gateway, etc.)
• No DECT support, and no direct fallback if the internet or UniFi Controller is offline
• May require workarounds for non-US regions or third-party SIP⸻
💡 Home Office Suitability
| Use Case | Better Option |
|---|---|
| Want full control, privacy, no recurring fees | ✅ Gigaset Fusion |
| Already using UniFi Dream Machine + want mobile app | ✅ UniFi Talk |
| Need DECT handsets (mobility around house or workshop) | ✅ Gigaset Fusion |
| Prioritise mobile & cloud convenience over local resilience | ✅ UniFi Talk |
| Need smart-home integration or Zigbee/ULE | ✅ Gigaset Fusion |
| Prefer an IP phone with touch display and mobile app backup | ✅ UniFi Talk |
⸻
🧠 Final Verdict
• Gigaset Fusion FX800W PRO is a better fit if you want:
• A resilient, localised system that doesn’t rely on cloud uptime
• DECT handsets and cordless operation
• Full PBX-style call handling without extra fees
• Better international compatibility (non-US SIP providers)
• UniFi Talk shines if:
• You’re deep into the UniFi ecosystem
• You want cloud-managed VoIP with mobile app support
• You don’t mind monthly costs and prefer ease of setup⸻
WHAT ABOUT GRAND STREAM ?
Short answer: over-kill at this time
Grandstream and Gigaset (formerly Siemens) both offer telephony solutions aimed at small businesses and home offices—but with very different design philosophies. Here’s a full side-by-side comparison focused on their high-end offerings for a modern, professional home office setup:
⸻
🥊 Gigaset Fusion FX800W PRO vs Grandstream UCM Series (and Accessories)
| Feature Category | Gigaset Fusion FX800W PRO | Grandstream UCM + GRP/GXV Devices |
|---|---|---|
| System Type | All-in-one desktop device: DECT + PBX + IP phone + smart hub | Modular: Separate PBX (UCM) + IP phones (GRP, GXV) |
| PBX Capabilities | Built-in (mini PBX, 6 SIP accounts, voicemail, routing) | Full-featured UCM PBX (Voicemail, IVR, ring groups, call recording, etc.) |
| VoIP Accounts | 6 SIP accounts, 4 concurrent calls | 200–2000+ SIP accounts depending on UCM model |
| DECT Support | Built-in DECT base (Cat-iq 2.1), up to 8 handsets | Only with DP752/DP760 DECT base (external unit) |
| Video Calls | ❌ No | ✅ Yes (GXV series phones) |
| App Ecosystem | ❌ None | ✅ GXV Android-based IP phones with apps, video conferencing |
| Touchscreen Phones | ✅ Built-in 5” screen | ✅ GRP and GXV phones (some models have 7” touchscreen + camera) |
| Wi-Fi | ✅ 2.4/5 GHz dual-band Wi-Fi built in | ✅ On some GRP/GXV models |
| Bluetooth | ✅ Yes (headsets, contact sync) | ✅ On some GRP/GXV models |
| FXO / Analogue Support | ❌ No built-in FXO | ✅ With models like HT813 or UCM6202 FXO ports |
| PoE Support | ✅ Yes (PoE Class 3) | ✅ Most Grandstream phones and UCMs support PoE |
| Smart Home Integration | ✅ Optional (Zigbee / DECT ULE) | ❌ None |
| Administration | Local web GUI + on-device setup | Web GUI for phones and PBX; CLI and provisioning tools |
| Licensing Fees | ✅ None | ✅ None (even for advanced PBX features) |
| Best For | Small home office with mobility needs and smart-home interest | Offices needing full PBX flexibility, video calls, and mix of phones |
⸻
🧠 Summary of Philosophies
✅ Gigaset Fusion FX800W PRO
• Strengths: Seamless all-in-one device, strong DECT integration, simple setup, elegant design, smart home integration
• Limitations: No video or app support, no FXO line, limited PBX flexibility✅ Grandstream (UCM + GRP/GXV/DP Series)
• Strengths: Powerful modular PBX, scalable, video calling, full SIP control, FXO/FXS options
• Limitations: More complex to set up, separate units needed (no true “all-in-one”), DECT is external⸻
🔍 Example Pairings
| Goal | Gigaset Setup | Grandstream Setup | Price ex VAT (UK) |
|---|---|---|---|
| Elegant all‑in‑one desk phone + cordless handsets | FX800W PRO + SL800H PRO handsets | Not applicable — needs separate DECT base & phone | Gigaset bundle ≈ £364 (bundle £437 inc VAT) |
| SIP PBX + FXO landline fallback | FX800W PRO + HT813 gateway (optional) | UCM6202 (built-in FXO) | UCM6202 ≈ £307 ex VAT (£368 incl VAT) |
| Video calls & Android phone apps | Not supported | GXV3380 IP phone with Android | GXV3380 ≈ £462 ex VAT (£554 incl VAT) |
| Small office with 4–10 phones | FX800W PRO + DECT handsets | UCM6204 + GRP2615 phones + DP752 base | — |
⸻
✅ Conclusion
• Choose Gigaset Fusion FX800W PRO if you want an elegant, zero-hassle, all-in-one SIP+DECT solution with no server and no cloud.
• Choose Grandstream if you need more flexibility, including video phones, multi-site deployments, or FXO/FXS integration, and are comfortable managing a more modular system.Would you like help configuring a Grandstream UCM setup or comparing a few specific models (like UCM6302 vs UCM6202)?
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BT Analog end of life
In the UK, BT is completely retiring analogue (PSTN) phone lines by January 31, 2027, with most customers—even those without broadband—being transitioned to digital landline services (VoIP) over broadband-managed networks . Here’s what you need to know:
⸻
⚙️ What Happens If You Don’t Have or Don’t Want Broadband?
• BT will still provide broadband (typically low-speed) as part of the phone service, at no extra cost 
• The traditional PSTN stop‑sell began in September 2023, and new analogue lines aren’t available anymore .
• If you currently rely on an analogue-only landline, BT will proactively contact you before migrating you to a digital solution .
I have not validated the above.===========================================================
All this said, a couple of SIP connected base with two DECT handsets would replace the existing for just a few bucks.
FOR EXAMPLE
For a SIP‑connected DECT base with two handsets, here are two solid Gigaset (Siemens) options:
🔹 Gigaset N300IP Hybrid DECT IP Base + 2 Handsets
• What’s included: N300IP DECT base station + two compatible handsets (e.g., C430HX, S650H PRO, R630H PRO). 
• Features:
• SIP VoIP support (up to 3 concurrent VoIP calls)
• Hybrid operation: also supports 1 analogue/PSTN call 
• Up to 6 DECT handsets
• HD voice, ECO-DECT power-saving, web provisioning  
• Pricing examples:
• S650H PRO bundle ≈ £129.90 ex‑VAT (£155.88 inc VAT) 
• R650H PRO rugged bundle ≈ £90 ex‑VAT (£108 inc VAT) ⸻
🔹 Gigaset N510IP PRO DECT IP Base
• What it is: VoIP-only DECT base (no analogue support) compatible with up to six PRO handsets. 
• Features:
• SIP support: up to 6 VoIP accounts, 4 concurrent calls
• PoE-powered, LDAP/online directory, email notifications 
• Excellent HD audio and enterprise-grade feature set
• Pricing:
• Base only typically priced around £56–£65 inc VAT (£47–£54 ex‑VAT) ⸻
✅ Quick Recommendation Table
| Option | Supports Analogue Line? | SIP Calls | Handsets Included | Price (ex VAT) |
|---|---|---|---|---|
| N300IP + 2 handsets | ✅ Hybrid (PSTN + SIP) | Up to 4 | 2 (choose C430HX/S650H/etc.) | ~£90–£130 |
| N510IP PRO + 2 handsets | ❌ VoIP only | Up to 4 | 2 PRO handsets | £47 (base) + handset cost |
🧠 Which One Should You Pick?
• Choose the N300IP if:
• You want the flexibility of analogue fallback (PSTN + SIP).
• You prefer simple plug-and-play bundles with handsets included.
• Choose the N510IP PRO if:
• You’re going fully SIP, no analogue lines.
• You want more scalability, power over Ethernet, and enterprise features.AND CHEAPEST - USE OLD HANDSETS WITH NEW BASE
✅ Solution: Use a SIP DECT Base Station
To migrate from analogue to SIP while keeping your existing DECT handsets, you need a VoIP-compatible DECT base that:
• Supports the CAT-iq 2.0/2.1 or GAP standard (most modern Gigaset handsets are compatible),
• Registers your old handsets,
• Connects to your SIP/VoIP provider over the internet.🔧 Compatible SIP DECT Bases (UK-friendly)
| Base Station | VoIP Support | Analogue Line? | Handset Compatibility | Price (ex VAT) |
|---|---|---|---|---|
| Gigaset N300IP | ✅ Up to 4 | ✅ Yes (hybrid) | Most Gigaset HX, GAP handsets | ~£45–£60 |
| Gigaset N510IP PRO | ✅ Up to 4 | ❌ No | Gigaset PRO + many HX models | ~£47–£55 |
🧪 How to Check Compatibility
1. Identify your DECT handset model (e.g., Gigaset A540, C430, etc.).
2. Check if it’s:
• GAP-compatible: most are.
• HX series: even better (HX = universal handset for VoIP bases).
3. Confirm base supports that handset (N300IP and N510IP cover most).➡️ Even older analogue Gigaset handsets often still pair successfully for basic calling (no phonebook sync or battery level display).
🧠 Example: Gigaset A540A user migrating to SIP
| Before | After |
|---|---|
| A540A base + handset | N300IP base + reuse A540 handset |
| Analogue landline | SIP VoIP provider i.e BT |
📌 Result: Same handset, new base, BT phone number
✅ Summary
Keep your existing DECT handsets by replacing the base station with a SIP-compatible model like the Gigaset N300IP FOR ABOUT £45