Tesunho's TM-981, TM-990, and TM-991 are three distinct car walkie-talkie models, each with unique features and specifications. Below is a detailed comparison of these products:

First. Appearance

·Weight and Dimensions:

TM-990: 72(H)×135(W)×199(L) mm, 882g

TM-991: 72(H)×65(W)×199(L) mm, 339g

TM-981: 55(H)×52(W)×198(L) mm, 245g

TM-990 is the heaviest and largest of the three, followed by the TM-991, while  TM-981 is the lightest and smallest.

·LCD Display:

Both TM-990 and TM-991 have larger 2.4-inch LCD displays. TM-981 is slightly smaller, at 2.2 inches. 

·SIM Card Slot:

The SIM card slots for TM-990 and TM-991 models are located at the top of the device, with an SD card slot located between SIM1 and SIM2. TM-981 has its SIM card slots on the back of the device and does not feature an SD card slot.

·Type-C Charging Port:

TM-981 has a Type-C charging port on the top for connecting a charging cable, a headphone, or an external speaker. However, TM-990 and TM-991 do not have a Type-C charging port.

·Knob & Buttons:

TM-981 features a multifunctional knob that adjusts the volume by rotating the knob in standby mode and navigates up and down through menu options when in the menu interface. Pressing the knob allows you to enter the menu or confirm a selection. In contrast, TM-990 and TM-991 models are equipped with dedicated menu, up, and down selection buttons, limiting the knob's function solely to volume control.

·Indicator Light:

TM-981 has an indicator light that serves a dual purpose, functioning both as a status indicator and as a back button.TM-990 and TM-991 have a dedicated Back button on the device, with the indicator light solely acting as a status indicator.

·Jack:

TM-991 is equipped with a 3.5mm headphone jack and a DC jack. TM-990 features an 3.5mm headphone jack and a USB port. Meanwhile, TM-981 featuring only a 3.5mm headphone jack.

·External Speaker Port:

The Advanced versions of TM-981 have an external speaker port on the left side for connecting to compatible external speakers. TM-990 and TM-991 models do not include an external speaker port.

Second. Accessories

·Mounting Bracket:
The Mounting Brackets for TM-981, TM-990, and TM-991 are all different in design. In addition to the standard bracket, TM-981 and TM-991 can also use a suction bracket, which provides more options.

·External Speaker:

TM-981 advanced version is equipped with an external extension speaker.

·Power Cable:

TM-981 supports 12V Power Cable While TM-990 and TM-991 work with 24V ones.

Third. Features

·Thunderstrike Protection:

 TM-990 and TM-991 both are equipped with thunderstrike protection, allowing them to operate in harsh weather conditions. TM-981 does not have thunderstrike protection.

·AI Noise Reduction:

With its AI noise reduction technology, TM-981 delivers superior audio performance by enhancing sound quality, optimizing volume output, and eliminating background noise interference.

·Special SOS Emergency Situation:

TM-981 will have flash show with red background.

·WIFI

TM-981 Support WIFI when TM-990 and TM-991 didnot have .With Wi-Fi capabilities, TM-981 easier integration into existing network infrastructures for optimal coverage and cost savings.

·Bluetooth

TM-981 can work with BLE Finger PTT . TM-990 can work with more bluetooth accessories like TH-P1 TA-B,While TM-991 didnot have .

·Secondary Development Pin

TM-990 has an additional 8-pin port at the back and there is a type C port below TM-981, the ports allow secondary development, such as connecting sensors or switching data transmission and control.

·Dual Audio Outputs:

TM-981 allows both the internal and external speakers to work simultaneously when an external speaker is connected. When an external speaker is connected, TM-990 and TM-991 internal speakers stop working.

Conclusion

TM-990 and TM-991 are more robust with lightning protection, making them suitable for harsh environments. On the other hand, TM-981 offers advanced features like noise reduction, WiFi, and Bi-amped functionality, making it a versatile choice for users who prioritize audio quality and connectivity options. The choice between these models ultimately depends on the specific requirements and preferences of the user.