Applies to: Only LT-3100S and LT-4200S in the cited editions; do not apply their procedures to non-S systems. LT-3100S: 95-102251 Rev1.09 (2025-04). LT-4200S: 95-104746 Rev1.00 (2024-11).
Work through these checks
LT-3100S · Dashboard / MSI
Dashboard separates System Units, Telephony, Data and BAM. Compare connected core units with the actual installation; an absent optional LT-3150S, LT-3140S or LT-3160S is not automatically a fault. Record Data status and RX/TX separately from SIP-line status. Messages > MSI is informational: browser viewing does not prove a message was read on the LT-3110S display. An unread-MSI alert still requires the operator’s attention.
LT-4200S · Dashboard / MSI
Dashboard should show the installed LT-4210S control unit and LT-4230 antenna; compare optional interface, alarm and printer units with the installation record. Preserve unit number, part number, serial and software version privately. The manual describes software propagation from the control unit to connected units; do not flash components separately. Messages > MSI is read-only information, not proof that an unread-MSI BAM alert is resolved.
When to stop and get help
A missing expected core unit or persistent alarm requires qualified marine GMDSS service. These checks do not certify the vessel’s operational readiness or approval.
What to tell support
Keep vessel identifiers, positions and diagnostic archives private. Preserve exact S model, manual edition, installed units, software versions, time and observed messages for authorized service.
Original troubleshooting guidance based on the official sources below. Menu names can change. This is an independent guide, not a manufacturer service bulletin or a bench-tested repair.