Device repair with serial TTL RS232

  • The required software and tools:SecureCRT,TFTPServer, serial port cable (connect with computer), TTL converter ,cross serial cable(connect with device),direct serial cable(connect with device).
  • Tools introduction:
  • Installation and configuration of SecuerCRT

1)Get the SecuerCRT package, installation according to clew click next, do not need to configure until completion.

2)Click the SecuerCRT icon,appear below pic,set serial port


Click File→connect,see as follow pic


Choose “sessions”,ans click(new session),see as follow pic


In the protocol options choose “serial”,and click next.


Notice: wo can look up our computer to choose which port is. my computer →device manager→port(COM and LPT),the default have com1 ang com2,so we can choose either of them.

Fill in the datas as the pic,cilck next


Click “finish”.

  • Installation and configuration of TFTPServer:
  • Get the TFTPServer package,and unzip it.
  • Click the “TFTPServer.exe”icon,see as below pic


Click (option),see as below pic


Log file name(L):this route is where you installation the TFTPServer

TFTPServer root:the route of upgrade program

  • The serial port cable which connect with computer(direct serial cable),show as below pic

resim8 resim9

Both ends of the serial cable for RS232 head.

  • TTL converter


The needs for TTL converter is not the same for different devices.

  • Cross serial cable and direct serial cable


Usually we just use 2,3,5.

2——RXD Receive Data

3——TXD Transmit Data

5——GND System ground

The cross connection method:2 connect with middle round hole of our equipments;3 connect with square hole;5 connect with the other round hole.

The direct connection method:3 connect with the equipment’s middle round hole;2 connect with square hole;5 connect with the other round hole.

Here we’ve already separated cross serial cable from direct serial cable,and signaled it.

The red stands for direct serial cable;blue stands for cross serial follow pic:


  • Next I’ll introduce our devices which needs TTL converter, which needs direct serial cable or cross serial cable.
  • When we use the TTL converter ,we also need use the direct serial port cable.

Support device: DVR5004A-B,DVR5008A-B,DVR5004C-B,DVR5008C-B,DVR5004C-S

DVR5008C-S,DVR5016C-S,DVR5004T-S,DVR5008T-S and so on.

The wiring pic as bellow,for example 5004T-S


Find the serial port, in the lower left corner of device


The whole of connection as follows


Here we use direct serial port cable,the other head of cable connect with TTL converter.


Above all those sets ,we have the environment to upgrade the device,connect COM1


Click “connect”,and reboot the device,see as follow pic tips


Press control+c, into the command line


When upgrading,make sure that the computer connect with device all the time.

Use “updata.img”package to upgrade the device.

Open “TFTPServer.exe”,and choose the right route where you put the program is

Input command:

U-boot # sip Ip is your computer Ip,you also can check it over the TFTPServer)


U-boot # lip Ip is dvr’s temporary Ip,make sure that it is in the same route with computer )

U-boot # run up (start upgrading)



After finish upgrading,it will return u-boot mode automatically,reboot the device.

  • It needs cross serial port cable when the TTL converter is not used.The cross serial cable connect with computer directly,and the other head connect with device.

Support device:DVR5004C-C,DVR5008C-C,DVR5016C-C.DVR5008E-S,DVR5016E-S,



DVR5116H-S and so on.

24 thoughts on “Device repair with serial TTL RS232”

  1. I purchased a Reolink Go but didn’t realize that I had to use a prepaid SIM card so it would not connect. I opened a ticket but didn’t get a response until the day I returned it. I will order another one and try again with a prepaid SIM card. I suggest that it is very clear on the Amazon site that you MUST use a prepaid SIM card.

  2. Thank you for the nice article. I am looking for a camera that records on SD and can be powered by power bank. The main use for it will be recording job interviews with new comers to insure no abuse is done to them. Can you please recommend some models with the Amazon link?


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.