Why the range looks confusing at first
Entel's intrinsically safe radio catalogue includes a large number of closely related model numbers, DT542, DT544, DT842, DT844, DT844FF, DT944, DT944FF, DT885M, DT982M, DX542-IS, DX544-IS and more, and at a glance these look like minor variations of the same product. Reading the model code itself resolves most of the apparent confusion, because Entel's naming consistently signals real differences in role, channel plan and certification level.
DT versus DX: handheld role
The DT prefix identifies Entel's core handheld transceiver line, portable units carried by an individual worker. The DX prefix, seen on models such as the DX542-IS and DX582M-IS, identifies a distinct product line within the range, and the specific certification and specification for a DX model should always be confirmed against its own listing rather than assumed to match a similarly numbered DT unit.
The M suffix: land mobile channel plan
Models carrying an M suffix, such as the DT885M, DT985M, DT582M and DT585M, are configured with a land mobile channel plan, typically a larger number of programmable channels, 16 or up to 99 depending on the specific model, intended for site-wide industrial or facility communication rather than maritime use. This is the variant most relevant to refineries, chemical plants, warehouses and similar onshore hazardous sites.
The FF suffix: marine channel plan
Models carrying an FF suffix, such as the DT844FF, DT944FF, DT985FF and DT 885 FF, are configured with a marine channel plan, addressing International, USA and Canadian marine VHF channels, including newer 4-digit channel numbering on current models, and are built for use aboard tankers and other hazardous-cargo vessels rather than shore-based industrial sites. This is the variant referenced in ASPL's own Entel brand content as suited to zones where a conventional radio cannot be carried aboard hazardous-cargo shipping.
Models without an M or FF suffix
A number of models, such as the DT542, DT544, DT842 and DT944, carry no M or FF suffix and are instead specified with an INT/USA/CAN marine mode plus private channel capability, effectively covering standard marine channel operation alongside a private, site-specific channel plan, positioning them between the pure land mobile M-suffix models and the marine-only FF-suffix models.
The IS suffix: an explicit intrinsically safe designator
The IS suffix, seen on the DX542-IS and DX544-IS, explicitly flags the model as intrinsically safe certified within Entel's naming itself, in this case to the UL913 standard rather than ATEX or IECEx, as covered in more depth in the dedicated certification-comparison article elsewhere in this series. It is worth noting that the absence of an explicit IS suffix on a DT-prefixed model does not mean the radio lacks hazardous-area certification; models such as the DT982M and DT944FF carry ATEX certification without an IS suffix in their name, so the certification itself should always be confirmed from the specification sheet rather than inferred purely from the model code's suffix.
The number itself: a rough tier indicator
Within Entel's naming, the numeric portion broadly tracks a feature and capability tier, with 9xx-series models such as the DT982M and DT944 generally offering higher gas-group ratings (IIC) and more advanced features than 5xx and 8xx-series models, which more commonly carry the IIB rating, though this pattern should be treated as a general tendency to confirm against the specific model's own certification rather than a strict, universal rule.
Using this to navigate the range quickly
- Onshore industrial site, land mobile channel needs: look for M-suffix models such as the DT885M or DT982M.
- Tanker or hazardous-cargo vessel, marine channel needs: look for FF-suffix models such as the DT944FF or DT844FF.
- North American site specifically requiring UL913 certification: look for IS-suffix DX models such as the DX542-IS.
- Always confirm the exact Ex marking or UL913 designation on the specification sheet itself before ordering, regardless of what the model code suggests, since certification is the detail that actually matters for compliance.
ASPL is an authorised distributor of Entel's full range in India and can help translate a model code into the specific configuration a given site actually needs.