TK-202 tracker

TK-202 tracker

Be warned: this blog post is not about software. It's about hardware!

Here's some usage instructions for TK-202 (or TK202) tracker manufactured by Xexun. Although Xexun offers user manuals on their web site, the manuals are far from perfect. By combining different manuals for different products, you can find almost all the information written below.

Some comments about the tracker

It seems that the tracker stays functional over 30 hours if it's only using GPS and GSM connections. I haven't tried to use it with the home station that would allow the tracker to shut down GPS (and maybe even GSM) modules.

The TK-202 is quite well built. However, it has some features I don't like too much. First of all, you cannot change the time or date shown by the watch. When TK-202 has a GPS signal, it sets the time automatically to the current time. I guess it should also change the date according the the GPS data, but I have never seen it working. The time is set to UTC (GMT) time and user has to configure the offset from UTC time to get the local time correctly shown.

Another disturbing feature is that the small buttons the watch has are very difficult to operate. If you manage to press the buttons, you don't get any feedback from the watch. There are two buttons on the side of the watch. One of them sends SOS message and the other shows current tracker coordinates. To show the current tracker coordinates, you need to hold down the coordinate switching button for a couple of seconds. If the tracker doesn't know it's coordinates, it just shows blank screen. When coordinates are shown, the tracker displays them with blue back light on the screen. You can easily send an SOS message by pressing a button, but there's no way to tell whether the watch really has sent the SOS message or not. To turn the tracker on and off, you have to hold down the both buttons simultaneously for some seconds. It seems that you must press the coordinate switching button just before pressing the SOS button. Otherwise the tracker just sends the SOS message and doesn't turn off. Even when the tracker is turned off, it uses a lot of battery.

Small side buttons

The worst feature of TK-202 is that it's quite bad in locating itself. I have been walking with the tracker by the sea (guaranteeing that there's nothing that could disturb the GPS signal) for more than half an hour and the tracker hasn't been able to find its location. If the tracker looses the GPS signal, it may not be able to recover or the recovery takes ages.



General  instructions for using SMS commands
The + sign used in the tracker SMS commands means that the text should be catenated together without any other characters such as space.

After each command, the tracker sends some form of OK message. Don't try to send more than one command at a time.

Tracker initialization

begin+password

When the tracker is in default configuration (first time use), the command is the following.

begin123456

Send this command after the tracker has acquired its position for the first time.

Changing the password
To change the default password, use the following command.

password+old password+space+new password

For example to change password from 123456 to 654321, send the following SMS.

password123456 654321

Adding authorized phone numbers
Authorized phone numbers are allowed to query tracker's position either by SMS or call (depending on the operating mode). Although authorization is required by some TK-202 features, it's generally not mandatory. To make all features easily  accessible from your own cell phone, you may authorize it (and by doing this, you also block random people from accessing your tracker).

admin+password+space+cell phone

For example, to authorize Finnish cell phone number 040 1234567 so that it would work also outiside Finland (i.e. using international format, the Finnish country code is +358), you could use the following.

admin123456 00358401234567

Note that the + sign is coded as double zeroes! The rest of the authorized numbers (there may be five at most) must be configured by the first authorized number.

To remove one authorized number,  send the following SMS (I haven't tried this).

noadmin+password+space+authorized number

To remove all authorized numbers, use normal begin command that was used when the tracker was taken into use (I haven't tried this). For example.

begin123456

Changing answering modes (positioning, monitoring, two-way calling)

For some reason the TK-202 manual does not tell how to set up two-way calling mode. This is weird, because on of the selling points of TK-202 is definitively the two way calling feature (I haven't found many watch trackers with microphone and loudspeaker that would allow user to make two way calls)!

There are three modes in TK-202 that I'm aware of: tracking, monitoring and two-way talk. When the tracking mode is on, the tracker sends its position as SMS when it's being called by an authorized number. In monitoring mode, the tracker hangs up when called by an authorized number and calls back automatically. When call is answered, the authorized caller is able to hear what's happening in the surroundings of the tracker. In two-way talk mode, a call from authorized number is automatically answered by the tracker and the caller and the person carrying the tracker may talk to each other. Here's how to change between the modes.

tracker+password
monitor+password
talk+password

For example.

tracker123456
monitor123456
talk123456

In my opinion, both the monitoring and two-way talking are very well implemented. There is a faint echo on the line, but it's still very easy to communicate.

Changing the time zone (to set the time shown by LCD display)


The tracker is showing time in UTC time, if not changed by configuration. You can set the time difference between UTC and local time with this command.

time zone+password+space+GMT time

For example, for Finnish winter time, you should use the following.

time zone123456 2

Use negative numbers for time zones "before" UTC.


Changing the SMS format sent by the tracker

This is also something that's completely missing from the TK-202 manual. User is allowed to change the format of the SMS sent by the tracker. Here's some instructions.

To get one Google map link from the tracker, send the following message.

smslinkone+password

To get the results always in Google maps format, send the following message.

smslink+password

To get the results always in plain SMS format (default mode), send the following message (I haven't tried this).

smstext+password

It's also possible to get a single SMS formatted message.

smsone+password

Tracking periodically

You can configure the tracker to send multiple location SMSs with one command. You can specify how many location messages you want and how often these messages should be sent. However, it seems that the tracker is somehow failing to count the number of messages correctly and you may get more messages than you requested.
The command form is the following.

tXXXsYYYn+password

The part XXX is number of seconds, minutes or hours that the tracker should wait between the messages. Replace s with m to get minutes and h to get hours, respectively. The YYY part is the total number of messages the tracker should send. Both XXX and YYY have range of 001 - 255 and you must always use three digits.

To turn of periodic tracking, use this command.

notn+password

Some features to be tried later

TK-202 may have the following features that I haven't tried them yet (I'm not sure as I found these from manuals for other products).

1. tlimit+password+space+distance in meters (for example tlimit123456 50)
• This command should set the tracker to alarm if it is being moved more than 50 meters away from the point where the command was given. Distance of 0 meters will cancel the warning.
2. GpsAutoSearch+password+space+120 (for example GpsAutoSearch123456 120)
• This command should change the refreshing frequency of GPS measured coordinates in seconds. The accepted values are between 120 - 600 seconds.
3. restart+password (for example restart123456)
• This command should remotely restart the tracker. Perhaps useful in some situations
• I tried this once and the tracker stopped functioning. The only way to get it working again was to remove the battery
4. volume+password+number
• This command should change the loud speaker volume. Accepted range is 0 to 99.
5. Some other commands? Geofencing is also interesting, but not useful for me...

Battery cover

Battery front

Battery back