card specific info

Novatel Merlin U630

The Merlin U630 is a standard PCMCIA-card. It's host interface is serial-over-PCMCIA. The operating system is seeing this card as any other serial device. If you open the device, the card is acting as a standard AT-compatible modem (or at least it looks like).

It has two interfaces:

- a modem interface

- a diagnostic (status) interface

Unforntunately the diag interface is of no use as it is expects specially encoded commands (the commands itself are really AT modem commands, but they have to be encapsulated into something what looks like ethernet frames). The encapsulation protocol being used is AFAIK known as CDPD.

As the manufacturer of this card (Novatel Wireless Inc.) does not document any single bit of information, you're on your own to get this card running or not. Novatel does not even respond to support requests nor do they have a documentation site. On their website they'll tell you in the FAQ you have to contact your network operator if you need to get any support (but the net-op's even don't have information about that card). Blame Novatel for that. If you have some spare time, drop them a message (probably best addressed to their CEO) and request support for free and open source operating systems.

Now back to the technical details.

You need to have sio or uart in your kernel for using that card. On insertion you should see a message like:

sio1: <Novatel Wireless Merlin UMTS Modem> at port 0x2f8-0x2ff irq 17 function 0 config 15 on pccard0
sio1: type 16550A
sio1: unable to activate interrupt in fast mode - using normal mode
pccard0: Allocation failed for cfe 7
pccard0: Allocation failed for cfe 15
sio2: <Novatel Wireless Merlin UMTS Modem> at port 0x2e8-0x2ef irq 17 function 1 config 23 on pccard0
sio2: type 16550A
sio2: unable to activate interrupt in fast mode - using normal mode

The device entry of interest is (in the above case) sio1 (as sio2 is the non-useable diag port).

But here your trouble may start... Unfortunately at least FreeBSD (5 + 6) as of 2006-09 still has a not fixed bug with sio. Please have a look at GNATS entry kern/51982. The sio driver is loosing received data because of a too small buffer. You may vote for this bug as it's really an old one and still not fixed. This bug will prevent all high speed devices using sio to fail.

Why bother with sio if there's uart? Well, currently (as of 2006-08) uart is still not complete and also has a bug. uart currently silently drops received data and as you won't see any console messages, you'll experience nothing but a not working connection. But in the future, uart will provide a good solution for 3G cards.

Merlin U630 commands:

- AT$NWRAT=x,y

Using that command you may set the card into GPRS only, 3G only or mixed (automatic) mode.

x = 0 (automatic), 1 (GPRS), 2 (3G/UMTS) mode

y = 0 (CS circuit switched mode), 1 (PS packet switched mode), 2 (automatic CS/PS)

So best is, if you want to set mode... use...:

GPRS only: AT$NWRAT=1,1

3G(UMTS) only: AT$NWRAT=2,1

automatic mode: AT$NWRAT=0,1

LED meaning:

red, constantly on: card is ready

green, blinking: GPRS signal detected, GSM network present

blue, blinking: 3G (UMTS) signal detected, network present

green, constantly on: registered into GPRS network (connected)

blue, constantly on: registered into 3G network (connected)

red + blue, rapidly blinking like hell: card has detected a stack fault (usually a protocoll failure). No way out from here. No packets will pass. The card is malfunctioning. In that case, you have to pull the card and re-insert it a few seconds later. I've seen that effect very frequent with firmware rev. 12.x and earlier. Using a firmware rev. 14.x (available at Vodafone New-Zealand website) this issue has become less often.

The datasheet for this card can be found at Novatel's site