Graves on SOHO Technology

Step 1: Get Another SIM Card

Last Friday I went down to my local T-Mobile shop and had my personal cellular plan converted to a family plan. Then I had them issue me a second SIM card, adding a new line to the plan. I told them that I’d use my old phone, an old Motorola Razr v3. I even brought it with me to the store. We used it to confirm that the SIM worked as expected.

Step 2: Install It Into The MV-370 GSM Gateway Device

Saturday afternoon I had a couple of hours to tinker with the gateway. I installed the SIM card, wired it up and applied power. Everything seemed correct but I could not get confirmation that it was on the T-Mobile network. This vexed me for an hour or more until I determined that I had the SIM card in backwards (Doh!). The SIM card slot in the gateway is not notched like it is in many cell phones.

Once I flipped the SIM card around the unit reported it was connected to T-Mobile and I was able to proceed with the basic software setup. The RF signal strength was reported as 16-18, which is well within workable range given in the notes I was working from.

Step 3: Configure The Gateway

Rather than add the gateway to my Astlinux setup I decided to add it to my Junction Networks OnSIP hosted IP-PBX account. This way I could experiment with it while traveling in the coming couple of weeks. Also, I didn’t want to break anything about my own server setup when I wouldn’t be around to fix it immediately. That would make my wife crazy.

Within the OnSIP admin portal I added another user and used those SIP credentials to configure the GSM gateway. That worked on the first try. I then setup very basic gateway routes for LAN-to-Mobile and Mobile-to-Lan calling. I’ll save describing all the details until the project is further along.

All I needed to get running in the first attempt was two-stage dialing. Two-stage dialing means that calling the number programmed into the SIM card would cause the gateway answer the call then immediately offer a second dial-tone. I then dial whatever call I want as if I was at my disk dialing on my Polycom IP600 SIP phone. The second call is placed over IP through OnSIP.

So far this works well. This is one of the major attractions of the gateway. It consolidates how I call my UK-based associates. For several years I’ve been using a calling card service to avoid the overseas long distance rates offered by the cellular carriers. This service brought my UK calling down from $0.25/minute to around $0.06/minute. That was pretty good but OnSIP provides calling to UK land lines at $0.029/minute. Even better.

Actually, it’s not hard to find even cheaper rates to the UK. Sometimes cost is not always the primary advantage. This GSM gateway project is principally intended to give us a wireless trunk should our IP connection go down. Remember that around my home & office we are sworn off POTS lines for a variety of reasons. No POTS lines since June 2005. It’s all IP. 100% VOIP. The wireless trunk will be very useful just as a backup connect method.

The other primary benefit of a cellular trunk is the ability to provide 411 and 911 service. We won’t be able to confirm that capability until I have some time to weave the GSM gateway into my Astlinux setup, which is a couple of weeks away at best.