[[TOC(Hardware/gDomains*)]]

== SB4 ==

As shown in Figure 1, sandbox 4 consists of 8 nodes and a WiMAX subsystem that consists of a basestation and a controller. To prevent interference, each node is housed in [http://www.ramseytest.com/ Ramsey Electronics RF enclosure] that provides 80 dB of isolation. Nodal wireless devices (Atheros 5000X mini-PCI card and Intel 6250 mini-PCIe 802.11/802.16) are connected to a power combiner and fed through the enclosure access port to the outside SMA connector which is wired to one of the input/output ports of the [http://www.jfwindustries.com/documents/50PMA-012_specsheet.pdf  RF Transceiver Test System] from [http://www.jfwindustries.com JFW Industries]. This configuration enables fairly tight control of RF attenuation matrix between the nodes. The topology is controlled through the [http://omf.mytestbed.net OMF] based [wiki:Documentation/Services/bInstrumentationControlService Instrumentation AM].

  || [[Image(SB4.jpg, 600px, link=, align=center)]] || [[Image(IMG_0376.jpg, 200px)]] ||

== RF Matrix Control Services ==

This service controls the RF attenuator matrix. Since there are a total of nine (9) input/output ports on the attenuator matrix, the first 8 input/output ports are connected to nodes 1 thru 8, respectively. The 9th input/output port is connect to the Wimax base station (BS).
 || RF Matrix Port || Attached device || Additional attenuation values (dB) ||
 || 1 || node1-1 || 20* ||
 || 2 || node1-2 || 20* ||
 || 3 || node1-3 || 25 ||
 || 4 || node1-4 || 30 ||
 || 5 || node1-5 || 20* ||
 || 6 || node1-6 || 20* ||
 || 7 || node1-7 || 10* ||
 || 8 || node1-8 || 0* ||
 || 9 || wimax BS || * ||

Attenuation values between each RF attenuator port (ie. the eight (8) nodes and wimax BS) can be controlled individually with the following URL commands listed below.

1. set - to set attenuation value on given port pairs (example portA=1 , portB=2, attenuation = 20)[[BR]]
This would set the attenuation value between node1-1 and node1-2 to 20 dB.

{{{
$ wget -O status http://localhost:5052/instr/set?portA=1\&portB=2\&att=20
}}}

2. get - to get attenuation on a given pair of ports

{{{
$ wget -O status http://localhost:5052/instr/get?portA=1\&portB=8
}}}

3. status - to get attenuation values on all port pairs

{{{
$ wget -O status http://localhost:5052/instr/status 
}}}