What’s Around the Corner?
I suppose this would not be a Leo Wrobel article without some glimpse of upcoming "Buck Rogers" technology. Accordingly, I will share an exciting morsel that I have encountered "by the water cooler." I would not be surprised to see people using it very soon.
"PRI on the Fly"
This is obviously not a term of art. The idea here is to connect a PRI (Primary Rate Interface, sometimes called a "smart T1") to a satellite link. "Hey, wait a minute, Wrobel," someone interjects. You said that streaming rates over satellite were generally limited to 256Kbs—and PRI is 1.536Mbs." This, of course is true if you use 64Kbs channels. But remember when I talked about voice compression earlier in the article? You don’t need all that bandwidth to carry voice. Besides, 256Kbs divides into 1.536Mbs very nicely, and equals 6. That means you need only 1/6 of the bandwidth to carry this hypothetical PRI. 64Kbs divided by 6 = about 10Kbs, more than enough for good voice quality with today’s technology and no additional delay (other than propagation to the satellite and back—about one-quarter second) because it is not based on IP packet or cell technology. In other words it works on paper, so how does one marry it to a PBX? That part as it turns out is pretty easy. A number of companies manufacture black boxes that convert raw bandwidth to the four-wire circuit and PRI signaling that your PBX expects to see. If you can restore a single PRI and its associated DID (Direct Inward Dial) numbers to a medium-sized hospital isolated by a telecom disaster, you have, for all practical purposes, restored communications to that hospital (the same for government offices, businesses, and essential services). That’s why I think this particular "PRI on the Fly" idea is really cool.