I have got as far as being able to communicate with the modem, I can dial up and establish a connection but I am having an issue with the communication protocol after this. I think it is causing a failure to authenticate whereupon the other end hangs up the phone after 4 or 5 seconds.
Here is list of what I am using.
- Normal analogue telephone line, nothing special about it, clear and has no noise
- UK Telephone Socket to RJ11 lead
- US Robotics 56k Message Modem
- RS232 DB9 to DB25 Null Modem Cable
- RS232 DB9 Gender Changer
- MAX3232 RS232 DB9 Serial Port To TTL Converter Module
- Raspberry Pi Model A
- Motorola Atrix Lapdock as a Console
I've also done a little hack to loop back the DSR to DTR pins (4 and 6) so that the modem will accept commands from the Pi. I then insert the Gender Changer into the female side of the null modem cable (shown below) which creates the short so that the DTR light on the modem comes on. Without this the modem doesn't respond to the AT command in minicom etc.
I know this might make some of you tut loudly but I can ensure that this wire is not shorting to any other pins.
Here is a list of things I have tested in isolation
- The TTL Converter Module works when connected to a PC serial port (Pi to PC)
- The Modem works when connected to a PC serial port (Modem to PC) AT OK etc
- The Modem works when connected to the Pi (Pi to Modem) AT OK etc
So on top of this I installed the ppp and wvdial packages. I am attempting to connect to this ISP and here is my wvdial.conf file. I have also been trying to use http://emergencyinternet.com/ and I get the same results, so I know something is wrong on my side.
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[Dialer Defaults] Modem Type = Serial Modem Phone = 08445352000 Baud = 115200 Auto Reconnect = yes Idle Seconds = 0 New PPPD = yes Init1 = ATZ Dial Command = ATD Auto DNS = yes Check DNS = yes Check Def Route = yes [Dialer modem] Modem = /dev/ttyAMA0 Carrier Check = no Username = free Password = dialup
I made a short video of this so you can see.
Here are some pics of the output too.
This one is with Carrier Check on; link.
This one is with Carrier Check off; link.
I have tried various different baud rates and these seem to produce no change.
So anyway I’ve been struggling with this for a while now and after tormenting a few of the chaps on IRC for several days with my pestering I thought it's time to try and consult the main forums. I hope someone out there might be able to help.
Any help or suggestion is really appreciated, thanks!