Signal Module

RhoElements 2.x API


The Signal Module is used to set position and display parameters of the wireless signal indicator on the screen.


signal (Module) <META> Syntax

<META HTTP-Equiv="Signal" content="[parameter]">

<META HTTP-Equiv="Signal" content="SignalEvent:url('[jsFunction | url]')">

Signal JavaScript Object Syntax:
By default the JavaScript Object 'signal' will exist on the current page and can be used to interact directly with the signal.
To Set signal parameters via JavaScript use the following syntax: signal.parameter = 'value'; remembering to enclose your value in quotes where appropriate.

e.g. signal.visibility = 'value';

To Set signal return events via JavaScript use the following syntax: signal.event = JavaScript Function;

e.g. signal.signalEvent = 'doFunction(%json)';

To set multiple EMML parameters / events on a single line use the following syntax: signal.setEMML("[Your EMML Tags]");

e.g. signal.setEMML("visibility:value;signalEvent:url('JavaScript:doFunction(%json)')");


Items listed in this section indicate parameters, or attributes which can be set.

NamePossible ValuesDescriptionDefault Value
visibility:[Value] Visible or HiddenSets whether or not the battery indicator is shownHidden
left:[Value] Pixel valueSets the horizontal position of the wireless signal indicator in pixels. If negative the indicator will be off the screenTop right of screen
top:[Value] Pixel valueSets the vertical position of the wireless signal indicator in pixels. If negative then it will be off the screenTop right of screen
layout:[Value] Left, Right, Up, DownSets the orientation of the signal icon.Right
color:[Value] Hex Values (#000000 - #FFFFFF)RGB value that sets the color of the wireless signal indicator using HTML web colors RR-Red, GG-Green and BB-Blue#000000


Values are returned to the caller in RhoElements via Events. Most modules contain events and those returned from this module are given below along with the event parameters. Events can cause a navigation to a new URL or a JavaScript function on the page to be invoked. Each event will in most cases have a number of parameters associated with it which will either be strings or JavaScript arrays. Event parameters can be accessed either directly or via JSON objects.


The SignalEvent gives an indication of the signal level and other associated information. Once registered for you will receive a SignalEvent at regular intervals, as specified by the SignalRefresh configuration setting.

1signalStrengthSignal strength value as a percentage
2essidCurrent ESSID
3macAddressWiFi MAC address
4adapterNameWiFi adapter name
5dhcpServerCurrent DHCP servers address
6dhcpStaticWhether the unit has a static or DHCP address
7gatewayCurrent gateway IP address
8ipAddressCurrent IP address
9rssiSignal strength in RSSI terms
10subnetMaskCurrent subnet mask
11winsCurrent WINs server IP address
12deviceHostNameHostname of the device. Supported only on Android Platform.



Do not display the Battery indicator overlapping with the Signal indicator.

Indicator Positions

For an illustrative guide to the meaning of the Layout parameter see the 'Indicator Positions' section.

Unavailable Data on ET1

The WINS server address and dhcpStatic data are not available on the ET1. Also the dhcpServer address is always populated, even on static IP configurations.

Parameter Deprecation

For users migrating their PocketBrowser apps to RhoElements please note that due to the difference in the signal indicator graphic, the GraphPosition and IconPosition parameters have been deprecated. Please use the Layout parameter instead.

Devices lacking support

Due to platform limitations this API is not available on the following Zebra Technologies devices on specific platform:

  • VH10 CE 6.0
  • Omnii XT15 CE 6.0


RhoElements Version1.0.0 or above
Supported DevicesAll supported devices.
Minimum RequirementsNone.
PersistencePartially Persistent - Changes to this module will persist when navigating to a new page with the exception of the return events.

HTML/JavaScript Examples

The following example shows the wireless signal indicator, sets the position to (50, 50), the color of the indicator beneath the bars growing from right to left:

    <META HTTP-Equiv="Signal" Content="Visibility:Visible">
    <META HTTP-Equiv="Signal" Content="Left:50">
    <META HTTP-Equiv="Signal" Content="Top:50">
    <META HTTP-Equiv="Signal" Content="Layout:Left">
    <META HTTP-Equiv="Signal" Content="Color:#FF0000">

Above example can also be written in EMML1.1 as given below

    <META HTTP-Equiv="Signal" Content="Left:50; Top:50; Color:#FF0000; Layout:Left; Visibility:Visible">

In EMML1.1 it is also possible to concatenate the Parameter with the module name. The example above can also be written as:

    <META HTTP-Equiv="Signal-Left" Content="50">
    <META HTTP-Equiv="Signal-Top" Content="50">
    <META HTTP-Equiv="Signal-Color" Content="#FF0000">

The following example navigates to a new page with parameters upon a wireless signal status change:

    <META HTTP-Equiv="Signal" Content="signalevent:url('mypage.asp?Signal percentage=%s&ESSID=%s&MacAdd=%s&Adapter=%s&DHCPServ=%s&Mode=%s&Gateway=%s&IPAddress=%s&RSSI=%s&Subnet=%s&Wins=%s')">