If both can talk to your computer through a max232, then they are both ttl devices. Pull the max232 out, and connect tx to rx and rx to tx and see what happens. Make sure they are both on the same voltage.
Walter
|
ttl to ttl
If both can talk to your computer through a max232, then they are both ttl devices. Pull the max232 out, and connect tx to rx and rx to tx and see what happens. Make sure they are both on the same voltage.
Walter
|
Thanks for the answer. The problem is that I am using a complete modem. I am sure it has MAX232 inbuilt. I just have to connect the rs232 serial cable to it and my pc. I cannot take out MAX232 from the modem.
It's pin 2 (DB9-connector) has a voltage of -5.85V.
Is it possible that I have to put more pins ground apart from pin5 of DB9-Connector? Thanks
___________________
WHY things get boring when they work just fine?
|
Although I am sure it works on PC with just TX, RX nd Gnd, have tried to connect to PC just with these 3 wires?
Also are you sure about 4800 baud?
Ioannis
|
I tried it now, I could not type in my hyperterminal anymore as soon as I connected my modem to the PC with only 3 wires. As soon as I connected 9 pin serial cable, everything starts working fine.Originally Posted by Ioannis
Yes, baud rate is 4800.Also are you sure about 4800 baud?
___________________
WHY things get boring when they work just fine?
|
Was hyperterminal in hand shaking mode?I tried it now, I could not type in my hyperterminal anymore as soon as I connected my modem to the PC with only 3 wires. As soon as I connected 9 pin serial cable, everything starts working fine.
See the modem manual, if the modem is in handshaking mode by default, in such a case you have to set it for no flux controll.
Al.
All progress began with an idea
|
I have not got the manual but I have opened the modem and saw that sim300 is the module which the modem is built on. I have checked sim300 datasheet but could not understand many things as I do not have too much of a technical background.
Can you advise me, what AT commands can do this job.
I also find this on the net - http://www.london-electronics.com/alpha_232_conns.gif
Is this an alternate way to go to solve this problem (RTC - CTS connected together & also pins 6,1,4 connected together? I do not want to try it unless it is safe to do so, only have 1 modem
Also, how can I find out if Hyperterminal is in Handshaking mode? One more thing I would like to mention here which I read from sim300 datasheet is that the modem supports and by default has Autobaud from 1200 to 19200.
___________________
WHY things get boring when they work just fine?
|
When you set the baud rate you can set also the flow mode. See the three snaps attached.Also, how can I find out if Hyperterminal is in Handshaking mode?
Al.
All progress began with an idea
Members who have read this thread : 0You do not have permission to view the list of names.
Posting Permissions
Bookmarks