Summit Knowledge Center

S Register

Command mode parameters and settings for modems and many wireless radios are stored in memory locations known as S Registers. They are labeled as S0, S1, S2, and so on. When a modem or radio is in Command mode, AT commands may rewrite the data values stored in S Registers to change connection parameters.

A detailed list of the definitions for a Summit and Laird radio's S registers may be found in the User's Guide for that radio.

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Save To... (SCU Diags window)

From the SCU Diags window, Save To... allows you to indicate where you want to save the diagnostics file. Tap Save open the Save As window. From here, you can change the SDC diagnostics file name, the folder in which SCU saves the file, the format in which the file is saved (the file type), and the location of the saved file (Main memory or System).

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When a Wi-Fi station device initializes, it must find an available access point for a connection. When the connection to that access point becomes tenuous, it must find a different access point that offers a better connection. The process of searching for an access point is referred to as scanning. There are two types of scanning:

  • Active scanning - For each channel on which an access point may be operating, the station transmits a probe request and waits to receive a probe response. Based on probe responses, the station determines the best access point to which it can associate.
  • Passive scanning - Instead of transmitting probe requests, the station listens on each channel for beacon frames transmitted at regular intervals by access points.

An access point responds to a probe request within 20 milliseconds (ms), whereas an access point may take 100 ms or longer to issue a beacon. Because a station spends less time on each channel waiting for information from access point, active scanning is more efficient than passive scanning.

Note: The number of access points identified during a scan and reported in the scan list found on the Profile Tab of the Summit Client Utility may vary due to a number of factors including interference in the environment, the type of microprocessor found on the host device and the priority the host device operating system affords the Summit device driver relative to other device drivers.

While doing active or passive scanning, a station device is incapable of sending and receiving "payload" data. Because of this, long scans have a negative impact on applications that require a persistent network connection. Devices that require high network availability should use Wi-Fi radios that allow scan times to be minimized.

In the 5 GHz band, DFS channels require passive scanning, because a station device may not issue a probe request or any other transmission on a DFS channel unless instructed by an infrastructure device that the channel is free from radar. Given that a passive scan may take hundreds of milliseconds per DFS channel, the use of DFS channels for highly mobile devices is discouraged, especially in the FCC and ETSI regulatory domains where there are 15 DFS channels.

Note: By default, dual-band Wi-Fi radios from Summit Data Communications turn off scanning on DFS channels.

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SCU (Summit Client Utility) is a connection management and monitoring utility that allows you to view all radio and security settings, and status; and enables you to troubleshoot connectivity issues.

For more information on SCU, refer to the SCU End User's Guide accessible from the documentation page of the Summit website:

Secure Simple Pairing (SSP)

A pairing protocol introduced in the Bluetooth 2.1+EDR release that increases security of Bluetooth pairing while making the pairing process more user friendly. There are several modes of operation for SSP, such as Numeric Comparison which displays matching pin codes on both devices to assure users that the correct devices are being paired. Additionally, Just Works mode allows devices to pair with no verification from a user for optimal simplicity.

Security Settings - SCU

SCU values for the two primary security attributes, EAP type and encryption type, are displayed in separate drop-down lists with the current values highlighted.

  • Encryption - When you select an encryption type that requires the definition of WEP keys or a pre-shared key (PSK), the WEP keys/PSKs button becomes active. Tap WEP keys/PSKs to define WEP keys or a PSK

    Note: Summit radios support two special access point settings:

    When running Migration Mode (which is Static WEP and WPA-PSK), a client using PSK fails to obtain an IP address (and therefore can't pass traffic). The issue may arise if the user is running both Migration Mode and Mixed Mode (Static WEP/WPA-PSK/WPA2-PSK).

  • EAP Type - When you select an EAP type, the Credentials button becomes active. Tap Credentials to define authentication credentials for the selected EAP type.

Serial Port Profile (SPP)

A Bluetooth profile dedicated to emulating serial port communication between two Bluetooth devices. In the profile, two roles are defined: Device A and Device B. Device A is the initiating device, and Device B is the device that awaits connection from Device A. When using this profile, the devices behave as though connected by serial port.

Shunt resistor

For the purpose of troubleshooting hardware, a shunt resistor is a small circuit that can be placed between two points of another circuit to measure the current passing through those points. By measuring the voltage drop across the shunt, the current can be calculated.

Signal Quality

A measure of the clarity of a radio's signal. Signal quality is determined by the number of beacons received versus the number of beacons expected over a set period of time.

In SCU, Signal Quality displays on the Status tab.

Signal Strength

See "RSSI".

Signal to Noise Ratio (SNR)

The Signal to Noise Ratio (SNR) is an arithmetic expression of the difference between the strength of a transmission (the signal) and the aggregate ambient noise (the noise floor). For example, if a signal is measured to be -50 dBm and the noise floor is measured to be -90 dBm, the SNR is understood to be 40 dBm (note that SNR is not so much a true ratio as it is a simple arithmetic difference). The greater the SNR the greater degree to which a signal may be modulated to support higher data rates and throughput. When the SNR reaches zero, a signal cannot be detected and a connection cannot be established or maintained.

Note: For Summit 30 Series radios the RSSI value displayed on the Status tab of the Summit Client Utility (SCU) takes into account the noise floor and so displays the SNR or the RSSI relative to the noise floor. For the Summit 10, 15, and 20 Series radios noise is not taken into account and an absolute RSSI is displayed. Therefore, the RSSI reported in SCU and compared to the Roam Trigger will be lower with the 30 Series than with the 10, 15, and 20 series. Other parameters related to scanning and roaming, such as Roam Delta, behave similarly for different radios under like conditions.

Single Channel Hop Measurement

Hopping Algorithm (79 Channel)

To measure hop timing using a 79 channel hopping algorithm, follow these steps:

  1. Connect the radio to the spectrum analyzer.
  2. Tune the spectrum analyzer to a Bluetooth channel (such as 2441 MHz).
  3. Set the span to 0Hz.
  4. Set the Resolution Bandwidth (RB) to ~100 kHz or 300 kHz.
  5. Set the Video Bandwidth (VB) greater than RB.
    Note: The RB must be set high enough to capture leading edges without capturing too much of the adjacent channels.
  6. Set the Sweep Time to a minimum of 5ms (greater than any Bluetooth packet duration).
  7. Start the EUT running its standard pseudo-random frequency hopping transmission pattern.
  8. Set the spectrum analyzer to Single Sweep.
  9. Set the spectrum analyzer to trigger off the RF level (this ensures that it triggers only when the EUT hops onto the tuned channel).
    Note: This process can be tricky. You must set a trigger offset to view the entire hop.
    This process should result in a pulse transmission screen on the spectrum analyzer.
  10. Place markers on the rising and falling edges of the pulse. The delta between the markers should be the pulse duration. The following indicates the desired DH packet measurements:
    • DH1: ~0.4 ms
    • DH3: ~1.6 ms
    • DH5: ~2.9 ms
    This process provides the timing of a single hop.

Pseudo-Random Hopping

To measure the number of hops on a single channel during full pseudo-random hopping, follow these steps:

  1. Connect the radio (EUT) to the spectrum analyzer.
  2. Tune the spectrum analyzer to a Bluetooth channel (such as 2441 MHz).
  3. Set the span to 0 Hz.
  4. Set the RB to ~100 kHz.
  5. Set the VB greater than RB.
  6. Set the sweep time to 79*0.4s = 31.6 seconds. Ensure that you have sufficient points on the spectrum analyzer.
  7. Start the EUT running its standard pseudo-random frequency hopping transmission pattern.
  8. Set the spectrum analyzer to Single Sweep.
  9. Capture a single sweep.
    Each time the EUT lands on tuned channel, there should be a spike on the plot.
    Note: There will be other spikes (at lower levels) that represent adjacent channels. Ignore these.
  10. Count the number of times that the EUT lands on the channel.
  11. Multiply that number by the single hop timing (from the 79 channel hopping algorithm above).
    This indicates the total time that the device is on one channel within the specified observation time. The total must be less than 0.4 seconds.

Sink (SNK)

One of the two roles of an audio device as defined by the A2DP Bluetooth profile. A device is the SNK when it receives the digital audio stream that is delivered from the source (SRC). For example, an in-car media player.

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smartBASIC is an event-driven programming language that enables standalone operation of the module that uses handlers to react to events. A simple smartBASIC application encapsulates the complete end-to-end process of reading, writing and processing of sensor data as well as advertising, connecting, security, power management, and wireless status. smartBASIC programs may then use BLE to transfer it to any Bluetooth v4.0 device - smartphone, tablet, gateway, or computer.


The Summit Manufacturing Utility (SMU) enables OEMs (device manufacturers) to set key radio parameters such as transmit power to compensate for antenna gain and channel set to maintain compliance with regulatory domain requirements.

Source (SRC)

One of the two roles of an audio device as defined by the A2DP Bluetooth profile. A device is the SRC when it is the source of the digital audio stream that is sent to the SNK. For example, a portable navigation device (PND).

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Sniff Mode

A power-saving mode of operation for Bluetooth devices. In Sniff mode, a device checks in preconfigured intervals for incoming data. The dormant periods are spent in a low-power state, allowing the device to save power when not transmitting. The Attempt, Timeout, and Max/Min Sniff intervals are configurable via AT commands and command scripts.

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Sniff Sub-Rating

An extension of Sniff mode introduced in Bluetooth 2.1 +EDR that allows extension of Sniff mode features. The Sniff Sub-Rating parameter allows the Sniff interval (sleep period) of a device to increase by factors after a defined period of inactivity. This is useful for certain devices (like a computer mouse) that may engage in a brief period of activity and then sit dormant for a long period.

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Software as a Service (SaaS)

Software as a Service (SaaS), sometimes referred to as "on-demand software", is a software delivery method that stores and maintains all software and its associated data on the cloud. In general, SaaS is used by users using a thin client via web browser.

Spatial Isolation

Spatial isolation is the notion of placing co-located Bluetooth and Wi-Fi radios (and their associated antennas) as far apart from each other as possible and, when possible, placing insulating material between them. Spatial isolation alone is rarely sufficient to achieve acceptable Bluetooth and Wi-Fi performance and is commonly employed in conjunction with other coexistence schemes. Spatial isolation is impossible with the latest generation of combination Bluetooth/Wi-Fi chips and modules.

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The Summit Regulatory Utility (SRU) assists OEMs (device manufacturers) with regulatory certification processes. SRU allows for radio operation in continuous transmit, continuous receive, and continuous wave frequency (non-modulated) modes which are typically required during the regulatory certification testing process.


Service Set Identifier. Unique name of up to 32 characters that identifies a particular 802.11 WLAN.

The SSID is attached to the header of packets that are sent over a wireless network.

Start Ping/Stop Ping (SCU Diags window)

From the SCU Diags window, Start Ping/Stop Ping allows you to start a continuous ping to the address in the edit box next to the button. Once the button is tapped, its name and function changes to Stop Ping. Pings continue until you tap Stop Ping , move to a different SCU window (other than Diags or Status), exit SCU, or remove the radio.

Note: If your device has both a Summit radio and another network adapter active, then pings may go out over the non-Summit network adapter.

Note: The access point's IP address is the default for a ping although any valid IP address can be manually entered.

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Stateful/Stateless Connections

When connections are made between systems, their connections are either stateful or stateless.

When the connected devices retain information about each other after the connection, and that information is kept for use in a later connection, this is known as a stateful connection. Human conversations are somewhat analogous to stateful connections. For example, If Person 1 tells Person 2 that his child has a cold, upon their next meeting Person 2 may ask how Person 1's child has been feeling lately. A connection is made, information is retained, and the information is used in the next connection.

In a stateless connection, however, neither party retains information after a connection is made and dropped. The bulk of the internet's basic protocols, like IP and HTTP, operate as stateless connections. Through extensions like browser cookies and other additional software, these stateless protocols may achieve stateful connections.


A WLAN-enabled client device or radio.

Status (SCU parameter)

Status is an SCU parameter that indicates the current status of the Summit radio. Radio status displays on the Main and Status windows of SCU.

Connection statuses include:


The radio is not recognized by Summit software and therefore is not associated nor authenticated.


The radio is disabled. To enable the radio, tap Enable Radio located on the SCU Main window.
When the radio is disabled, it does not attempt to make a connection to an access point.

Not Associated

The radio has not established a connection to an access point.


The radio has established a connection to an access point but is not EAP authenticated. The radio can not communicate unless it is associated and EAP authenticated.

Note: If the Encryption type is set to WEP or Open (None), it can communicate (send data) while in the Associated state.

<EAP type> Authenticated

The radio has established a connection to an access point and has completed EAP authentication successfully. In this state, the radio can communicate (send data).

Status Window - SCU

The SCU Status window provides status information on the radio connection between the station and the access point to which it's associated.

The following Status parameters are displayed on the Status tab of the Summit Client Utility:

Stereo Streaming

Audio system with two separate audio signal channels which are used to replicate the exact sound of the original noise when passed through an appropriate audio receiver. Applications include smartphone speaker docs, wireless hi-fi audio systems, automotive multimedia devices, and stereo headsets.

Stop Bit Delay

Controls the width of the last bit before the stop bit occurs in a transmission.

Sub-Band Codec

SBC, or Low Complexity Sub-band Coding, is a digital audio encoder and decoder for Bluetooth that supports both mono and stereo channels. It transfers data to Bluetooth-enabled audio output devices (like headphones or loudspeakers) and is the default codec for Bluetooth audio because its use is mandatory for many supplementary profiles. It is to be used with the Advanced Audio Distribution Profile (A2DP).

Summit Radio Certifications

In order to better serve our customers, Summit Data Communications makes available multiple versions of the same core product. These versions typically provide for alternative physical interfaces and/or multiple antenna options. In all cases, the radio performance of the various versions is identical to the radio performance of the core product.

As such, and where applicable, Summit uses the certifications, grants, approvals, and other related items of the core product for the various versions of that core product.

The following table describes each originally-certified Summit device and the Summit devices that fall under these certifications.

Core Product

Description Type

Associated Versions


802.11a/g Compact Flash Module with Antenna Connectors

Certifications for the SDC-CF10AG apply to the following devices:

  • SDC-CF22AG - 802.11a/g Compact Flash Card with Integrated Antenna
  • SDC-PC10AG - 802.11a/g PCMCIA with Antenna Connectors
  • SDC-PC22AG - 802.11a/g PCMCIA Card with Integrated Antenna


802.11g Compact Flash Module with Antenna Connectors

Certifications for the SDC-CF10G apply to the following devices:

  • SDC-CF20G - 802.11g Compact Flash Card with Integrated Antenna
  • SDC-CF22G - 802.11g Compact Flash Card with Integrated Antenna
  • SDC-PC10G - 802.11g PCMCIA Module with Antenna Connectors
  • SDC-PC20G - 802.11g PCMCIA Card with Antenna Connectors


802.11a/g Mini Compact Flash Module with Antenna Connectors

Certifications for the SDC-MCF10AG apply to the following device:

  • SDC-MSD10AG - 802.11a/g Mini SDIO Module with Antenna Connectors


802.11g Mini Compact Flash Module with Antenna Connectors

Certifications for the SDC-MCF10G apply to the following device:

  • SDC-MSD10G - 802.11g Mini SDIO Module with Antenna Connectors


802.11a/g Mini SDIO Module with Antenna Connectors

Certifications for the SDC-MSD30AG apply to the following device:


802.11n PCI Express Mini Card with Antenna Connectors

Certifications for the SDC-PE15N apply to the following devices:

  • SDC-EC15N - 802.11n ExpressCard with Antenna Connectors
  • SDC-EC25N - 802.11n ExpressCard with Integrated Antennas


A supplicant is a user (client) making a request to gain access to system resources through the authentication server.

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Symbolic Link

A symbolic link is a file which acts as a shortcut or stand-in for another file, linking the two. A symbolic link is created through a computer's operating system, and acts as a stand-in file path for the target path that it is linked to. For example, the path for C:/folder/folder2/folder3/folder4/folder5/program.exe can be joined to a symbolic link at C:/programlink. Symbolic links are useful in that they can behave as shortcuts to other locations. They are supported in Linux, Mac OS X, and Windows Vista/7.


A process by which collocated servers can become in tune with one another and avoid each other's presence when frequency hopping, thus eliminating overlap and minimizing the chance for interference.

Synchronized Connection-Oriented (SCO) Link

A Bluetooth protocol that is used as a radio link for voice data.