hi,
I have a PIC communicating with a SE T630 Handphone via the good ol MAX232 ( I did an SMS control system)
This board worked fine when I used it about 6 months ago. Everything was going smoothly, SMS control could be initiated.
However, recently when I got back to using my setup again, the communication some how seemed to have a sort of "intermittent" problem with the handphone.
The serial connector to the handphone type is a snap-on version. So I snapped on the serial connector head to the port of the handphone but my board did not indicate communication (each successful AT configuration I indicated with a blink of an LED).
I had to adjust the snapped on head in a "sweet spot" and then, only did the board indicate communication (blink the amount of times required.) So ,I held it in it's "sweet spot" using an elastic band and everything worked fine. SMS control could be achieved in my system once again.
So I wondered what the problem was, I checked the communication of the handphone with Hyper Terminal and the communication with Hyper Terminal was flawless. AT commands were transmitted to the phone, Responses were received without any flaw. Did not require me to adjust the snapped on cable head in a sweet spot for it to communicate. Only when I connected it back to my board did I have to hold it with an elastic band.
The problem gets worse, After a few weeks, communication could no longer be established with the board no matter how I held it in with an elastic band. So I wondered if it was a phone problem.
I went to a 2nd handphone dealer and borrowed a similar SE phone model, I snapped on the cable and voila, communication was established. No need for elastic band...However, the downside was that this phone only supports PDU mode. I developed my program in Text mode. So I had to return the handphone.
I recently purchased a another SET630 2nd hand and it worked flawlessly with Hyper Terminal. I plugged it with my board and now the board is not detecting anything.
So im wondering if the SET630 handphone has a tendency to have defects where it works well with a PC but not a MCU? I know it sounds very fishy but Im sure my board is working because it worked before. And I've troubleshooted the board for sleepless nights. All the connections and required voltage levels are fine.
So I was wondering if it was the RS-232 voltage levels differing between the MAX232 output and that of the board. For as long as the voltage level is below -3V, a Logic 1 should will be registered (EIA-RS232 specs ).I measured both the output of the MAX232 and the PC Serial Port. Both gave me an approximately -6V reading. Should not be a board problem
So my question (finally) is ...has anyone expereinced this sort of thing before? Could it possibly be a problem of the phone itself? (some internal hardware/software defect)
Should I spend more cash to get another phone and test it out?
if it helps the cable looks like this (see link)
**broken link removed**
The end=)
I have a PIC communicating with a SE T630 Handphone via the good ol MAX232 ( I did an SMS control system)
This board worked fine when I used it about 6 months ago. Everything was going smoothly, SMS control could be initiated.
However, recently when I got back to using my setup again, the communication some how seemed to have a sort of "intermittent" problem with the handphone.
The serial connector to the handphone type is a snap-on version. So I snapped on the serial connector head to the port of the handphone but my board did not indicate communication (each successful AT configuration I indicated with a blink of an LED).
I had to adjust the snapped on head in a "sweet spot" and then, only did the board indicate communication (blink the amount of times required.) So ,I held it in it's "sweet spot" using an elastic band and everything worked fine. SMS control could be achieved in my system once again.
So I wondered what the problem was, I checked the communication of the handphone with Hyper Terminal and the communication with Hyper Terminal was flawless. AT commands were transmitted to the phone, Responses were received without any flaw. Did not require me to adjust the snapped on cable head in a sweet spot for it to communicate. Only when I connected it back to my board did I have to hold it with an elastic band.
The problem gets worse, After a few weeks, communication could no longer be established with the board no matter how I held it in with an elastic band. So I wondered if it was a phone problem.
I went to a 2nd handphone dealer and borrowed a similar SE phone model, I snapped on the cable and voila, communication was established. No need for elastic band...However, the downside was that this phone only supports PDU mode. I developed my program in Text mode. So I had to return the handphone.
I recently purchased a another SET630 2nd hand and it worked flawlessly with Hyper Terminal. I plugged it with my board and now the board is not detecting anything.
So im wondering if the SET630 handphone has a tendency to have defects where it works well with a PC but not a MCU? I know it sounds very fishy but Im sure my board is working because it worked before. And I've troubleshooted the board for sleepless nights. All the connections and required voltage levels are fine.
So I was wondering if it was the RS-232 voltage levels differing between the MAX232 output and that of the board. For as long as the voltage level is below -3V, a Logic 1 should will be registered (EIA-RS232 specs ).I measured both the output of the MAX232 and the PC Serial Port. Both gave me an approximately -6V reading. Should not be a board problem
So my question (finally) is ...has anyone expereinced this sort of thing before? Could it possibly be a problem of the phone itself? (some internal hardware/software defect)
Should I spend more cash to get another phone and test it out?
if it helps the cable looks like this (see link)
**broken link removed**
The end=)