Motorola provided the highest throughput of any product in our roundup. Running at a modulation scheme of 256QAM, the PTP 600 provides a data rate of 300 Mbps. As expected, adding attenuation to our cabled setup caused the radios to operate at less-efficient modulation schemes, with a range of throughput from 190.73 Mbps to 277.93 Mbps.
Along with high throughput, Motorola easily delivered the low latency values needed for VoIP applications (sub-millisecond in our tests). Because our test bed didn't allow for actual physical distance between radios, which eliminates latency due to RF signal propagation time, we asked Motorola what its customers report as typical latency times. The company claimed latency of less than 2 ms to 4 ms, depending on link and traffic load.
Motorola offers a wide array of connectivity features in its radios. IP traffic can be sent over Category 5 as well as fiber optic links. Motorola also provides a T1 interface to send TDM traffic over the wireless link. TDM traffic, which often carries voice, can be prioritized over IP, while IP traffic can also be prioritized using 802.1P QoS. The PTp 600's fiber connection allowed us to sidestep the problematic Cat-5 we ran into in our initial testing.
Motorola's Web interface provided extensive troubleshooting and configuration options; in addition to listing current status--including modulation scheme, data rate and more--Motorola provided historical data for both monitoring and troubleshooting purposes. This would be handy, for instance, to determine if RF conditions caused a hiccup in service during off hours.
Motorola's PTP 600 radios are available in both 5.4-GHz-band and 5.8-GHz-band versions and can be purchased in both integral (with an antenna) and connectorized (for use with external antenna) models. The FCC has not authorized the 5.4-GHz PTP 600 radio for sale in the United States; however, the unit is certified for use in Canada.
