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Grandstream HT841: four FXO lines, one FXS port and lifeline mapping

Keep four PSTN-facing FXO ports distinct from the single FXS device port, three SIP profiles, per-port routing, bridge or router mode, lifeline relay and HT8x1 firmware state.

Reviewed 2026-10-24Grandstream exact-family HT841 and HT881 product information, datasheet, September 2026 user manual, FAQ, quick-installation and provisioning guidance, firmware 1.0.11.8 release notes dated August 14, 2026, and the UCM interconnection guide updated May 4, 2026 were reviewed October 24, 2026. Model, hardware, FXO line, FXS device, SIP profile, identity, registration, peer trunk, port mapping, PBX route, PSTN state, lifeline mode, firmware, provisioning, signaling, media, fax and accepted service remain separate evidence. Grandstream sources conflict on whether the two Ethernet ports are 10/100 or 10/100/1000; exact hardware, negotiated link and interface status must be inspected rather than inferred. Published defaults and capabilities do not prove installed configuration, compatibility, capacity, availability, provider approval or a successful change. No gateway, line, analog device, cable, network, PBX, account, packet, call, fax, outage, firmware image, checksum, price, inventory, support entitlement or vendor response was inspected or testedIntermediateDocumentation based · not lab tested

Documented specifications

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Grandstream · Grandstream maintains a current shared product record, September 2026 manual and August 2026 firmware record. Those records do not establish installed hardware or firmware, local availability, provider approval, support entitlement or remaining service life.

HT841: manufacturer-sourced facts
SpecificationDocumented value
Analog ports4 FXO ports for PSTN or traditional-PBX lines plus 1 FXS port for an analog phone or fax; the roles are not interchangeable Source ↗
SIP profiles3 SIP profiles are documented through the gateway; profiles are not physical ports, identities, registrations or concurrent calls Source ↗
Network-source conflictThe current product page and datasheet describe two 10/100/1000 ports, while the FAQ says two 10/100 ports; inspect the exact unit and negotiated link Source ↗
TopologyBridge is the documented default; router mode and DHCP behavior are configuration choices, not proof of the deployed boundary Source ↗
Lifeline relayHT841 maps its FXS port to FXO4 for lifeline operation; configured mode and an observed outage outcome remain separate evidence Source ↗
Fax capabilityT.38 is listed; negotiation, fallback and successful page delivery require separate evidence Source ↗
Firmware identityRelease 1.0.11.8 dated August 14, 2026 names ht8x1fw.bin for HT841 and HT881 Source ↗
Activation defaultsThe 1.0.11.8 release notes publish Profile Active and Enable Port defaults as No; published defaults do not establish effective local state Source ↗

Unlisted fields remain unverified. Platform compatibility and remaining support life require confirmation for the exact ordered model.

Start with the FXO and FXS boundary

HT841 presents four FXO ports for PSTN or traditional-PBX lines and one FXS port for an analog telephone or fax. An FXO line port cannot power an analog endpoint, and the FXS port is not a fifth PSTN input. Record the printed model, hardware, serial or MAC, every physical connection and the status page before moving a cable.

A four-line gateway, three SIP profiles and one FXS device path describe different dimensions. None alone establishes identity count, registration count or concurrent-call capacity.

Map each line, SIP port and PBX route

For every FXO port, preserve the PSTN number or circuit label, redacted SIP identity or peer target, local SIP port, inbound forwarding or DID treatment and outbound PBX route. Grandstream’s UCM example derives an FXO SIP port from the base plus two for each successive port; confirm the effective base and port ID rather than copying example values.

Peer or no-registration trunks and registered extensions are distinct designs. A working registration does not prove inbound forwarding, outbound line selection or PSTN answer and disconnect behavior.

Resolve the first-party Ethernet conflict locally

The current product page and datasheet describe two 10/100/1000 Ethernet ports, up to 1000 Mbps in bridge mode and up to 100 Mbps in NAT mode. The current FAQ instead says two 10/100 ports. Preserve that conflict: inspect the exact hardware, labels, status page, negotiated link and mode rather than silently selecting one publication.

No published interface figure proves application throughput, and bridge versus router mode determines a different network boundary.

Treat lifeline as a physical and configured path

The manual maps HT841 lifeline operation between its FXS port and FXO4. It also documents Auto, Always Connected and Always Disconnected modes. Record the physical FXO4 line, effective mode, normal-power behavior and an authorized outage test separately.

The presence of a relay or a configured option does not prove that the intended PSTN line, analog device or outage workflow will operate.

Bind firmware and activation state to HT8x1

Firmware 1.0.11.8 is dated August 14, 2026 and names ht8x1fw.bin for HT841 and HT881. The release notes also publish Profile Active and Enable Port defaults as No. After any authorized update, compare the effective profile and every FXS or FXO port state instead of treating download, reboot or a reachable web interface as completion.

Preserve the source, filename, published MD5, transfer result, reboot event, installed version, configuration and rollback or recovery plan.

Accept line service one direction at a time

Pilot each intended inbound PSTN call, outbound PBX-to-PSTN selection, caller ID, digits, answer, disconnect, two-way audio and restart persistence. Test the separate FXS phone or fax path and any required T.38 negotiation without inferring success from a capability flag.

LEDs, web access, registration and firmware version are useful states, not accepted service. No gateway, PSTN line, analog endpoint, call, fax, outage or firmware change was tested for this reference.

Sources & applicability

Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.

Examples require adaptation to your topology. No live PBX or hardware testing is claimed.

Continue your research

Troubleshooting · Grandstream exact-family HT841 and HT881 product information, datasheet, September 2026 user manual, FAQ, quick-installation and provisioning guidance, firmware 1.0.11.8 release notes dated August 14, 2026, and the UCM interconnection guide updated May 4, 2026 were reviewed October 24, 2026. Model, hardware, FXO line, FXS device, SIP profile, identity, registration, peer trunk, port mapping, PBX route, PSTN state, lifeline mode, firmware, provisioning, signaling, media, fax and accepted service remain separate evidence. Grandstream sources conflict on whether the two Ethernet ports are 10/100 or 10/100/1000; exact hardware, negotiated link and interface status must be inspected rather than inferred. Published defaults and capabilities do not prove installed configuration, compatibility, capacity, availability, provider approval or a successful change. No gateway, line, analog device, cable, network, PBX, account, packet, call, fax, outage, firmware image, checksum, price, inventory, support entitlement or vendor response was inspected or tested

Grandstream HT841 or HT881 routes the wrong PSTN line, loses lifeline or stops calls after firmware

Find the first mismatch in FXO versus FXS role, per-port SIP and PBX routing, bridge or router mode, physical lifeline mapping, activation state or HT8x1 firmware evidence.

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Device reference · Grandstream exact-family HT841 and HT881 product information, datasheet, September 2026 user manual, FAQ, quick-installation and provisioning guidance, firmware 1.0.11.8 release notes dated August 14, 2026, and the UCM interconnection guide updated May 4, 2026 were reviewed October 24, 2026. Model, hardware, FXO line, FXS device, SIP profile, identity, registration, peer trunk, port mapping, PBX route, PSTN state, lifeline mode, firmware, provisioning, signaling, media, fax and accepted service remain separate evidence. Grandstream sources conflict on whether the two Ethernet ports are 10/100 or 10/100/1000; exact hardware, negotiated link and interface status must be inspected rather than inferred. Published defaults and capabilities do not prove installed configuration, compatibility, capacity, availability, provider approval or a successful change. No gateway, line, analog device, cable, network, PBX, account, packet, call, fax, outage, firmware image, checksum, price, inventory, support entitlement or vendor response was inspected or tested

Grandstream HT881: eight FXO lines, one FXS port and lifeline mapping

Keep eight PSTN-facing FXO ports distinct from the single FXS device port, three SIP profiles, per-port routing, bridge or router mode, lifeline relay and HT8x1 firmware state.

Eight-port FXO gateway with one FXS port
Grandstream maintains a current shared product record, September 2026 manual and August 2026 firmware record. Those records do not establish installed hardware or firmware, local availability, provider approval, support entitlement or remaining service life.

Read guide →
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