The Nokia Mediamaster 9850T was one of the first ONdigital receivers released to the market, alongside the Philips and Pace models, and one of the first digital terrestrial receiver that Nokia had made.
Like other ONdigital boxes, the 9850T uses SECA Media-highway for its middleware, alongside the MediaGuard conditional access system. The box also has a PCMCIA slot for future digital interfaces, likely to enable upgrades. The front panel design is similar to the other models of the time, all boxes had a Power, Select, Menu and directional buttons to allow basic control of the receiver without a remote, and a 4 digit display which would show the channel number and the time in standby
Front View

Rear View


Lifting the Lid

Tuner Block

The tuner is implemented on a separate module away from the mainboard, it seems the board is based off the 9800/9700 satellite receiver, and when it came to adapting the design for the 9850T, Nokia added the DVB-T tuner module as a separate module. This module is soldered in and cannot be removed.
Motorola MC92314 – Datasheet

The modem is also a separate component, connected what looks like an internal RS232 port, to the left you can see spaces reserved for the satellite tuner modules

Shot of the CPU and MPEG2 decoder, cannot find any other chips unless they are on the underside, so I assume this also contains the decoder.
Texas Instruments TMS320AV7110
From looking at the datasheet below, the CPU of the box is based on an ARM design and runs at 40.5MHz


Sony CXA20920 – AV encoder

Front panel display

Another shot of the main CPU and MPEG2 decoder, the Flash and RAM chips can be seen to the left side

The modem module itself
Size Comparison
Vs Pace Di4000


Vs Pace 2500S5


Conclusion
As this was one of the first DTT receivers on the market, the box seems to be quite primitive compared to the later Freeview receivers with its lack of a full EPG and more importantly 8K tuner support, however in the ONdigital era the Nokia was considered to be the more reliable and supported box (The Sony and Toshiba models did not get MHEG support) and there are reports of the 9850T being able to lock onto weaker signals better than its Philips or Pace counterpart.
The addition of the digital audio connecter would have been the main distinction from the other ONdigital boxes besides the Sony, since they were the only models to feature this.
Nokia would later go on to continue creating DTT receivers for the Freeview service, with models like the 221T or the 121T, which had an unorthodox and unique design compared to the traditional 9850T. Unfortunately Nokia exited the Freeview market after 2005, along with its satellite receivers and focused on mobile phones before Microsoft purchases their handset division. It’s not known it Nokia will reenter the set top box market.