I bought a Sprint PCS
Merlin C201 PCMCIA card for my laptop, so I could
get wireless internet access wherever there is Sprint PCS coverage.
I don't use MS Windows or any other Microsoft software, but the Merlin
is only supported under MS Windows, hence this document.
It turns out the Merlin can be used with Linux...
Sean Reifschneider has figured out how to resolve the problems mentioned below. You should look at the following page before reading my page further:
First I called Sprint and activated the Merlin. After taking my information, the Sprint rep gave me a 6-digit activation code (an MSL), then transfered me to tech support.
I couldn't get my Merlin to do anything under Linux, and the tech support couldn't help. Eventually, I tried setting up my Merlin on a friend's Windows XP machine using the CD that comes with the Merlin. The first few steps of the install process on XP worked, and I was able to program the 6-digit MSL number into the Merlin. However, when I tried to connect to the internet using the Merlin under XP, I received an error message about my username and password not updating correctly. In the end I couldn't get my Merlin to work with Windows XP. I tried calling tech support, but hung up after being put on hold for nearly an hour.
I then put my Merlin back into Linux, and it appeared as /dev/ttyS3. (It will probably appear as something different for you; look in the log messages, and replace /dev/ttyS3 by your device everywhere below.) I configured my modem program (minicom) to use that serial port at 57600 bps. It worked fine, and I was able to dial my ISP. In particular, the built in modem is not a winmodem. However, as a modem it is very slow, only 14.4kbps. Incidentally, if you don't have an ISP you can still connect to the net this way using these instructions. However, one really wants packet-switched mode, which is much faster, and for that see below.
I surfed the web some and played around and discovered the following. The modem automatically "goes online" when it is inserted in the machine. I tried to start pppd (version 2.4.0, incidentally) to connect to /dev/ttyS3 as follows:
/usr/sbin/pppd /dev/ttyS3 57600 defaultrouteIn my kernel log messages I see
Aug 27 01:09:49 localhost pppd: pppd 2.4.1 started by root, uid 0 Aug 27 01:09:55 localhost pppd: Using interface ppp0 Aug 27 01:09:55 localhost pppd: Connect: ppp0 <--> /dev/ttyS3 Aug 27 01:09:55 localhost /etc/hotplug/net.agent: assuming ppp0 is already up Aug 27 01:09:59 localhost pppd: local IP address 22.214.171.124 Aug 27 01:09:59 localhost pppd: remote IP address 126.96.36.199
Something happened! When I try it additional times, I get a similar local IP address, but the last three digits vary.
Typing route, I see:
Destination Gateway Genmask Flags Metric Ref Use Iface 188.8.131.52 * 255.255.255.255 UH 0 0 0 ppp0 ...I try pinging 184.108.40.206, but nothing happens! Argh.
I then give up and start searching online for some hints, and end up loging into my Sprintpcs Vision account. Part of the login procedure requires me to select a password, which I evidently haven't done yet. I do so, and explore that page, but find nothing too useful. I then retry my Merlin and pppd, and I'm able to ping 220.127.116.11! I have no idea whether or not setting my password had any affect. I doubt it now.
For some reason, 18.104.22.168 doesn't act as a gateway, so I do a port scan and get this:
[root@laptop merlin]# nmap -sT 22.214.171.124 Starting nmap V. 3.00 ( www.insecure.org/nmap/ ) Interesting ports on (126.96.36.199): (The 1599 ports scanned but not shown below are in state: closed) Port State Service 23/tcp open telnet 1723/tcp open pptpThis scan suggests that I'll have to set up a complicated pptp client. I tried, and wasn't able to get that to work. Fortunately, the solution was much simpler.
One hour later I tried pppd again and pinging no longer worked. I couldn't get it to work. I didn't understand at all why pinging temporarily worked...
I think the pinging-or-not problem is a reception issue. If I execute the command
/usr/sbin/pppd /dev/ttyS3 57600 defaultroutewith my hand held firmly on the antenna and the antenna pointed toward my window, then it usually works; if I don't, then it often doesn't work. I only have to hold the Merlin's antenna while I wait to connect, not later. Moreover, I do nothing further and I'm able to connect to computers all over, i.e., packets are forwarded just fine. This is a little strange because, e.g., I have not logged into the network using my "Sprint Vision Password".
I did figure out how to log in to the network using CHAP, by inserting the line
PDSN wstein01 my_passwordin my chap-secrets file and executing the command
/usr/sbin/pppd /dev/ttyS3 57600 defaultroute user wstein01
You can watch the log messages for pppd by using the debug option to pppd, adding the lines
local2.* /var/log/ppp daemon.* /var/log/pppto /etc/syslog.conf, and restarting syslogd. You see that Sprint's ppp server requests CHAP authentication, and if you give it the wrong password, it will reject you. It's not necessary to set this stuff up though; presumably the Merlin has built in hardware-level authentication.
You can also watch traffic over the Sprint Merlin using the command
tcpdump -i ppp0
[root@laptop bin]# more go-merlin su -c 'killall pppd; sleep 3; \ /usr/sbin/pppd /dev/ttyS3 57600 debug defaultroute; \ tail -f /var/log/ppp' [root@laptop bin]# more stop-merlin su -c 'killall pppd; m'
Merlin C201 and MacOSX From: Larry Barras
To: email@example.com I was rummaging around for info on the C201 and hit your page. I thought you might find it interesting that Apple included a modem ccl file for the C201 (Sprint Vision in the modem list). Once the card was activated on a PC, just pop it into a PowerBook, open the PPP control panel, select pc-card-serial, enter the sprintpcs user name and password and that's it. I wish there were utilities to monitor reception levels and so on as the PC software has, but it seems to work just fine as a modem. ------------------------------------------------------------------------