Table of Contents

Tait TM8200 Series

The Tait TM8XXX series are “PMR” radios that have become popular with Amateurs due to their excellent performance, modern architecture and flexibility. Many of the TM8200 series support MPT-1327 trunking and were often used by large organisations (Notably London Buses until a few years ago). They come up less frequently than their TM8100 counterparts, presumably due to stricter disposal practices - but they do come up now and again and can be programmed with conventional FM channels with all the benefits and features of the TM8100s.

One thing worth noting is the Graphical Display Heads frequently have faulty LCD displays, leading to vertical blank lines. This can vary in severity and in all but the most severe cases the radio will still be usable.

Images

A Tait TM8235 with a 3 digit standard control head:

A Tait TM8255 with graphical display control head:

Models

The TM8200 range consists of several models listed below

Model Notes
TM8235 100 Conventional Channels, 4 MPT Networks, Standard Display Head
TM8250 1500 Conventional Channels, Graphical Display Head
TM8255 1500 Conventional Channels, 4 MPT Networks, Graphical Display Head
TM8252 1500 Conventional Channels, 4 MPT Networks, No Display Head (RJ45 Only)

They are available in the following frequencies. The radio identification or frequency range can usually be found on a sticker on the base of the radio. Watch out for the C0 “Band 3” models which are outside of the amateur bands.

Identification Frequency (MHz)
A4 66-88
B1 136-174
C0 174-225
D1 216-266
G2 350-400
H5 400-470
H6 450-530
H7 450-520
K5 762-870 (Tx) 762-776 and 850-870 (Rx)

Power Requirements

The radio will operate on 10.8V to 16V and RF power output is stable down to 12v.

The table below shows the relationship between RF output and DC power in. Note it may not be entirely accurate, but should be good enough.

Watts Out Amps In
1 1
5 1.5
12 2.5
25 3.5

TODO: Check idle power TODO: Confirm still valid for 8200 TODO: VHF / UHF?

Pinout

The 25 watt TM8200s use a Molex Mini-Fit Jr connector. Replacements are available on eBay, or if you wish to make your own the housing is part number 39-01-4040 and the pins are 39-00-0078.

The pinout is as follows:

Auxiliary Connector Pinout

The simplified pinout:

Pin Use NinoTNC pin
7 Transmit Audio (Input) 1
12 PTT 3
13 Receive Audio (Output) 5
15 GND 6

The full pinout:

Programming Cable

It was previously understood that the TM8XXX series required inverted 3.3v serial in order to program them, however the “Computer-Controlled Data Interface (CCDI) Protocol Manual” shows that the serial Rx line is RS232 level compatible. A tear down of a commercially sold programming cable also revealed a MAX232 type chip, confirming the radios can tolerate high levels than 3.3v. This means that instead of trying to find an invertable, 3.3v serial adapter, you can just adapt an RS232 cable to the pinout of the radio assuming it'll work with receiving the lower voltages. Fortunately Most modern USB to RS232 adapters will work fine.

The pinout to program the radio via the RJ45 connector on the front of a TM82XX can be found below:

Hints

Control Head Notes

Packet Configuration

The TM8200 Programming Application is slightly different to the TM8100 version owing to the trunked mode. Settings are split into 3 sections, Global, Conventional and Trunked. You can switch them by pressing the appropriate button in the top left corner of the software:

Global Settings

Specifications

Select the band for the radio your programming, usually B1 for VHF of H5 for UHF. Note this must match the hardware you're programming.

UI Preferences

Backlight Mode - Off (Optional, but worth considering for radios that just sit on a single channel to extend life / avoid it becoming a distraction)

Start-up

Power On Mode - Power On (Ensures the radio comes back on after a power outage) / Previous State (Switches on if it was previously switched on) Start-up Mode - Conventional. It's unlikely you'll be using trunked mode.

PTT

External PTT(1)

PTT Transmission Type: Data Audio Source: Audio Tap In

Programmable IO

Digital

Aux GPI1: Direction = Input, Action = External PTT 1

Audio

RX: Tap Out = R2, Tap Out Type = Split, Tap Out Unmute = Except on PTT

EPTT 1: Tap In = T13

Conventional Features

Networks

Basic Settings

Basic Network Settings

Set the Tx Timer and Lockout values to a sensible duration.

Channel Setup

Channels

The channels configuration is fairly intuitive. Set the appropriate frequency and bandwidth.

The detailed tab provides more options:

Conv Key Settings

Key 1 - Squelch Override. Useful for debugging weak stations.

Conventional UI

Set startup channel to the desired channel if you're operating as an always on node.