Teltonika TRM240 USB LTE modem

Teltonika is a telecommunication equipment manufacturer based in Lithuania. In this review, we test the TRM240 USB LTE modem that works on GSM 2G, 3G and 4G LTE mobile networks.

Teltonika TRM240 specifications
Connection USB
Frequency bands 900, 1900, 2100
Network protocols GSM, GPRS, UMTS, EDGE, HSDPA, HSPA+, LTE-CAT1

Other Teltonika models only offer partial SMS functionality

We have also tested other Teltonika modems and routers with Diafaan SMS Server but found that the SMS support in other models are incomplete at best. The Teltonika TRM250 modem misses options like USSD and we encountered firmware software issues with the modem chip that made SMS less reliable.

Some Teltonika mobile routers, like the RUT240 router, supports SMPP which can be used with the basic- and full editions of Diafaan SMS Server. But in our tests, the SMPP implementation was limited to outgoing messages only, incoming messages and delivery reports were not supported.

Setting up the Teltonika USB modem

Teltonika TRM240 USB modem

Teltonika TRM240 USB modem

The Teltonika TRM240 modem came with an antenna and USB cable and was easy to set up. The modem does not need an external power supply, it is powered by the USB connection. On Windows 11 it was necessary to install the USB driver from the Teltonika website. Once the driver is installed, the modem was immediately recognized by Windows. Diafaan SMS Server found the TRM240 without any problems, the modem identifies itself as a Quectel EC21 modem module.

Daily operation

During our tests the Teltonika TRM240 modem worked without any problems. The modem supports the full reboot command from Diafaan SMS Server after the modem encounters a problem. It also recovers well after the USB connection has temporarily been disconnected. All SMS features that Diafaan SMS Server supports are handled well and the modem also supports USSD. The SMS send speed of the Quectel modem module is very high, at least on the Vodafone 4G LTE network that we used for testing.

SMS send speed

Network Vodafone
Signal quality Average
Time to send 500 messages of 160 characters, delivery confirmation enabled. All messages sent to the same number (concurrent send and receive) 3 minutes 41 seconds


The Teltonika TRM240 4G LTE USB modem supports all SMS features, is very fast and is therefore an excellent choice for use with Diafaan SMS Server.