uplcom(4) problem

Rahul Siddharthan rsidd at online.fr
Tue Oct 5 21:38:28 PDT 2004

The situation is this: looking for home internet access, I went in for
a wireless phone with inbuilt modem (seemed the best option in my part
of town).  The modem is widely reported to work with linux, and works
with a generic modem driver in windows.

The phone/internet company supplies a cable with that phone, which
only connects to a serial (9-pin RS232) port, which my computer
doesn't have.  So I bought a USB-to-serial connector, a noname chinese
thing based on the Prolific PL-2303, both linux and DragonFly
recognise it and configure a serial port (under DF it's the uplcom
driver and the device is /dev/ucom0).  

However, I'm not able to send commands to the phone.  Running
ppp(8) with a config file says the initialisation command for the
modem (AT+CRM=1) timed out.  Typing "term" while inside ppp(8)
just causes ppp to hang, has to be killed from another xterm.

The same thing happens with linux and pppd/wvdial: the initialisation
command times out.

Under windows, it goes through fine, the dialling takes under half a
second.  I'm not using the ISP's "official" software to connect, but
the generic modem driver and a manually supplied initialisation
command (but I am using the supplied drivers for the USB-to-serial
device I bought separately.)

Any idea what could be wrong?  It seems to me that the modem is not at
fault, but the USB-to-serial is not sending commands to the modem.
Any way I can track it down?


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