Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Problem with using Siemens C55 mobile with 8051

Status
Not open for further replies.
K

kishorekhatri

Member level 1
Joined
Nov 8, 2006
Messages
36
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,503
i have check more than 6 "siemens C55 "cell phone to use MC 8051,, but when ever i connect it with hyper terminal to check for AT command it get OFF,,,when i click on call in hyper terminal it get off,, ,i checked many cell phones but all have sam prob ,, plzzz help.........
 

siemens serial cable voltage

The phones operate at 3 volts. What level converters did you use?

You can not directly connect to 5 volts driven lines. Could try using series connectors 22k in each line connected to the phone (except GND).

hope this helps and best regards
 
Re: help,, siemens C55

The phones operate at 3 volts. What level converters did you use?
Click to expand...


but i m using cable which direct connected to RS232 PC
 

Re: help,, siemens C55

Do you mean original Siemens data cable?
 

help,, siemens C55

no its not orignal siemens data cable ...
 

Re: help,, siemens C55

There are two kind of C55 data cable:

one is normal serial port cable, it has no any problem when connected to HyperTerminal.
and other one is USB to Serial cable, this last cable has trouble with HyperTerminal.

Which cable do you use?
 

Re: help,, siemens C55

i have cable , which is not orignal, and its is RS232 (DB-9) connector.,, i think the wires in this cable are direct connected and NO voltage convertor is there ,, if i connect i this way as shown in figure then , will cell phone work properly with hyperterminal ???
 

Re: help,, siemens C55

Your cable can't connect your cellphone to PC properly.

PC COM port is a RS232 port, that mean recoqnize voltage <-5 Volt as logical '1' and voltage >+5 Volt as loginal '0'
Cellphone serial port is low voltage digital device, voltage >2 Volt as '1' and <8 Volt as '0'

You have to use Voltage Converter to interface cellphone to PC, one of the circuit is :
23_1166413467.jpg

Note : ignore MBUS from above circuit

or use MAX3232, MAX3280
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top