High Speed Multi Media (HSMM) is primarily used under FCC Rules & Regulations Part 97. Under Part 97 commercial off-the-shelf equipment can be used at higher power and higher gain than the more common Part 15 802.11a/b/g operations.
The primary purpose for HSMM is to augment emergency communications via long range high speed wireless data networks that can handle voice, data and video communications. HSMM can also be used in the day-to-day aspects of Amateur Radio Communications.
With the rapid expansion of Asterisk PBX into the realm of radio communications the added flexibility of having a wireless linking system has also expanded. It is now possible to have a network of repeaters and link stations that never touch a standard public switched telephone network, yet at the same time this network of repeaters and link stations has all the standard features one will expect to find with any telephone system.
By integrating HSMM along with Asterisk PBX a truly transportable network can be delivered to any location where communications is needed, with voice, data and video all being available to the agencies and organizations being supported.
What is needed to initialize HSMM network?
Basic Off-The-Shelf equipment will work with HSMM, one thing to remember is to find equipment that have external antenna jacks available (one of the most common type of antenna connectors in use is R-SMA).
- The Linksys WRT54G is one gateway that is mentioned as a being a good choice because of its expandibility.
- Consider a high-gain parabolic dish antenna for point-to-point links
- When possible mount all the RF equipment as close to the antenna and use POE (Power over Ethernet) to limit cable signal loss.
|HSMM 802.11(a),(b),(g) under FCC Part 97.311|
|802.11(a)||12 Channels Non-Overlapping||5.650 – 5.925 GHz||OFDM||1500 W PEP|
|802.11(b)||8 Channels Overlapping||2.390 – 2.450 GHz||DSSS||10 W PEP 1|
|802.11(g)||8 Channels Overlapping||2.390 – 2.417 GHz||OFDM||1500 W PEP|
|OFDM : Orthogonal Frequency Division Multiplexing|
|DSSS : Direct Sequence Spread Spectrum|
|(1) 97.313(j) changed to maximum of 10 W PEP (4MAR2011)|