- Bargraph-Display fixed. One segment was aktivated to much.
- Infotext (Hotkeys and programnames) will not be overwritten by the used unit after the first sweep any more.
By pressing the menue key twice you get a stable "unit display" instead.
- Number of custom usable floatingpoint variables increased from 16 to 32.
- WLan hotkey (key 6) sweeptime changed to 5s (was 1s).
- CLR hotkey (key CLR) span changed to 700MHz-2,5GHz (was 0-4GHz).
- DECT hotkey (key 0) nuw runs backwards to prevent displayproblems in the LCS software.
- Marker Count funktion integrated. MrkCnt is used to set the number of markers. Possible values are 1,2 or 3.
If you only need to measure one frequency you should reduce the number of markers to "1". You then get a very stable display with no
"jumping" markers after every sweep.
- Marker-frequency resolution expanded. Now frequencys below 1000MHz are always shown with one decimal place.
- When you press, for example, the GSM900 hotkey (7), the text "GSM900" was displayed in the large
info field. This text will now be overwritten after the next sweep be they used unit e.g. dBm.
- Brightness option integrated. The new menue "Bright" allows you to change display brightness.
Simply turn the Jog Dial until the desired brightness level is reached, and confirm the setting by pressing the enter key.
The new setting will be permanently saved.
- We set the accuracy of the RBW filter to typical +/- 0,1dB. You should now get same results on 100kHz to 3MHz fiter.
Integrated software support for REVISION 3 of the optional REALTIME PEAK power detector (new HARDWARE required!) - available for up to 10GHz!.
A hardware update to REVISION 3 is possible at any time! See our specifications for Revision 3 and our new pricelist for details!
The new software provides you with the following NEW modes of operation:
- Bargraph display of the PEAK dBm reading from the power detector AND spectrum analysis SIMULTANEOUSLY
- ULTRA FAST! REALTIME display of the time domain (level change with time) from the power detector
(starting from 10mS!!), or:
- "Slow" time domain display (up to approx. 10s)
Time domain display speed can be changed at any time using the "SpTime" menu item, from 10mS!! up to 10s.
The following software changes in this firmware apply to ALL SPECTRAN versions:
- Signal detection and signal display have been completely overhauled. Display of various digital
signal types is now far more "natural". For example, a WLan signal is now shown as a nice "brick",
as it should be, instead of a "hill".
- The real noise floor is now determined before each measurement, using the attenuator circuitry, potentially yielding a higher sensitivity.
- Various improvements in the software can slightly improve sweep speed, depending on the actual settings.
- HOLD mode now also incorporates marker display.
- The hotkey "6" has been adapted for 2,4GHz WLan measurement (formerly sweep from 5-6GHz). Actual values are as follows: "fstart=2400, fhigh=2490, sampletime=500mS, pulse=on, RBW=3MHz"
- The menu entry "Disp" has been renamed to "Hold", subentry "PkHold" has been renamed to "On" and
"Write" has been renamed to "Off".
- The "MPMode" menu has been renamed to "MrkDis" (Marker Display Mode).
- The "Marker" menu has been renamed to "MrkLvl" (MarkerLevel).
Small bugfix in filetransfer from Spectran to PC (did not affect measurement result transfer though).
Marker level has been extended from -80dBm to -90dBm, thusly also extending the W/m² display mode by "10dB", as this mode uses the markers as basis for its calculations.
- Maximum sensitivity: As a result from a lot of inquiries, here are a few examples how to increase and often surpass the typical sensitivity:
Center frequency: 2GHz
Span = 10MHz
RBW = 100kHz
VBW = 100kHz
Sampletime = 0.05s
Sensitivity can very well go beyond -90dBm typical when using the HF-4040 or a better model.
- Optimum settings for WLan or GSM uplinks:
For all manual haters, we provide the optimum settings again here: the correct frequency or frequency
ranges can be found in the manual or in the frequency list on our homepage. These can be set
using fLow and fHigh.
Now, additionally change the following settings:
RBW = 3MHz
Pulse = PULSE (PEAK on)
Sampletime = 0.5s
The correct Sampletime setting is of particular importance here.
Of course, it's even easier to just use our PC analysis software, where all required settings for various types of signals are already available as pre-installed profiles, including PEP measurement. A single
"click" is enough.
Spurious signals at approx. 5.6GHz removed.
- Wrongly labelled menu entry "SwTime" has been corrected to "Sptime" (Sampletime).
- Bargraph scaling activated. Scaling reaches from -100dBm to 0dBm. As a result, SIMULTANEOUS display
of THREE seperate units is now possible. For example, in exposure limits mode, SIMULTANEOUS display of
dBm (bargraph), V/m (main display) and W/m² (pixel display) can be set. What other device can do this?
- The V/m display now has an auto-range feature. The maximum display range has thus been extended
to 999.9V/m, while formerly being limited to 9.999V/m.
- The mA/m display now has an auto-range feature. The maximum display range has thus been extended
to 999.9mA/m, while formerly being limited to 9.999mA/m.
- New feature "Sweep interrupt via USB". With this feature, the sweep can now EXTERNALLY
be interrupted via the USB interface. This is extremely helpful for the PC analysis software
and allows an IMMEDIATE, fluid parameter transfer without latency. Until now, changing parameters
could be a little bothersome as one had to wait until the sweep ended.
- Power flux density display has been enhanced with the new unit pW/m². As a result,
the maximum display range has been enhanced down to 0,01pW/m² = 10fW/m² (f=FEMTO). This
corresponds to just 0.000,000,000,000,001 W/m².
- The last error in the attenuator calculation has been fixed. Display in "auto mode" should now
- Error in PC analysis software data transfer (slotanalyzer mode). DECT & Co. again display
- Cable SETUP has been added. From now on, complete calibration data for antenna cables can be recalled. The connected cable MUST now be chosen in the new menu entry "cable", as otherwise severe
mismeasurement can occur. In contrast to antenna setup, cable setup ALSO influences the dBm display.
The following "cable" options are available:
"NONE" = NO cable connected
"1m Std" = the 1m SMA cable provided with the product
- Integrated DATA LOGGER (only HF-4040 and higher!).
ATTENTION: For OPTIMAL results, you should DEFINITELY equip SPECTRAN with our optional 1MB memory
expansion (Option 001), as the default 64K can quickly be used up!
Use the new menu entry "Logger" to permanently log the highest marker and the corresponding frequency
with each sweep (you can even store completely different or several values, as the logger software
can even execute other programs! However, you would need to develop your own software for this).
The included STANDARD LOGGER works as follows:
After activating the logger feature, you need to enter the following parameters:
"COUNT" = Number of sweeps (runs) that should be logged.
"TIME" = Pause time between the individual "logs" in seconds.
"FILEId" = The program number under which the data should be stored. This number MUST be bigger
than 1000! Using this same number, you can later on transfer the data using the PC software.
The logger is now "live" (the memory status field displays "RECORD"). Press the menu button once
again, and recording commences. During recording, the remaining number of logs will be
briefly displayed with each log in the pixel display (counter). This allows you to monitor how long
the recording is still going to take. Furthermore, each log event produces a short beep. When recording
is finished, "RECORD" will disappear from the display and the data can be downloaded via the
- Slightly increased noise floor around 2.4GHz has been fixed, allowing decent measurement of
2.4GHz WLan even with very weak signals
- DECT analyzer improved once again: the Time-Domain feature has been enhanced to a resolution of
100nS. For example, this provides the ability to measure the FULL bandwidth of DECT (24! channels). Especially using the SPECTRAN PC analysis software, you can now do impressive displays and analysis.
- New 20dB and 30dB attenutators (ONLY for HF-6080!). The 30dB version is right now still "inaccurate",
thus please use with care...
- A new "AUTO attenutator" feature has been integrated into the "Atten" menu. When enabled, levels
are AUTOMATICALLY monitored during measurements and the corresponding attenuators are AUTOMATICALLY
chosen when necessary to protect the device.
- With activated attenuator, power flux density calculation and display are now automatically
- LOW bat display added. When battery voltage drops below 6.6V, "LOW" is displayed next to the
battery symbol, giving you approximately 10 minutes of remaining operating time.
- Display contrast adjustment has been extended. On very low battery (LOW display), display contrast
will be given an additional boost.
- Missing calibration data for the HyperLOG 7060 antenna has been added and can now be chosen
as "HL7060" in the main menu under the "AntTyp" entry.
- In AUDIO mode, when changing RBW (cursor up/down keys), the newly chosen RBW is now
displayed in clear text on the large info display.
- In AUDIO mode, when changing the center frequency (cursor right/left keys), the newly chosen
frequency is now displayed in MHz on the large main display.
- When you press, for example, the GSM900 hotkey (7), the text "GSM900" is displayed in the large
info field. Until now, this text has been erased after leaving AUDIO mode. This has now been fixed.
The text will now be displayed as long as configuration is unchanged.
- All known USABILITY problems should thus be fixed now. Should you have a suggestion anyway - please contact us!
- The long expected cursor feature has been added. As an additional goody, a practical zoom feature has been added as well. Works as follows:
The cursor is activated with a press on the "Jog Dial" (volume control), and deactivated with the
menu key. The cursor is displayed as a small line and is initially positioned on the highest peak.
By turning the jog dial, its position can be changed as desired. Now, the main display, exposure limit
display and demodulation ONLY correspond to the current cursor position! The current cursor frequency
is displayed in the first (left) marker field after each sweep. As a consequence, the auto marker
feature is always deactivated in this mode.
After positioning the cursor, you can press the jog dial again, and the CENTER frequency will be
moved to the current cursor position resp. frequency, the SPAN is halved and a new sweep is initiated.
In other words, you zoom into the signal by 50%. You can repeat this procedure as often as you wish until
the desired resolution is reached. A very practical feature.
You can deactivate the cursor at any time by pressing the menu key twice.
ATTENTION: The cursor is NOT erased in HOLD mode!
- Antenna SETUP has been added. From now on, complete calibration data for the included
HyperLOG antennas are available as presets. The corresponding antenna MUST now be chosen using the
"AntTyp" menu entry, as otherwise, among others, severe mismeasurement in power flux density may occur. However, the dBm display would not be affected by such mismeasurement. The following antennas
"NONE" = NO antenna connected, or an antenna with 0dBi gain
"HL7025" = HyperLOG 7025
"HL7040" = HyperLOG 7040
"HL6080" = HyperLOG 7060 & HyperLOG 6080
- USB protocol finished. A specialized PC analysis software and a complete description
of SPECTRAN's firmware API and the USB protocol for developing your OWN software for PC and SPECTRAN
will shortly be available for free download.
- Based on suggestions, menu navigation has been made a lot more comfortable: When browsing menu entries, the current setting of each menu option is now displayed in the upper, large info field, freeing you
from the burden of manually checking each value. ATTENTION: Sweep time is displayed in mS, however, ENTRY
is still performed in seconds. Consequently, when entering 0.1, the display will show 100 (meaning
- The DECT analyzer has been improved once again. Pulse analysis and the corresponding filters
have been vastly improved, giving SIGNIFICANTLY greater speed: a complete sweep of ALL
10 DECT frequency blocks now finishes in less than 2 seconds!
- When setting SPAN to 0, a new, SUPER FAST measurement mode is available, finally giving SPECTRAN's
DSP the chance to show off its true performance: display is now virtually REALTIME (of course you
would also have to set sweep time to 0.1 or smaller!). But notice: when levels now change very quickly,
the display will now update so fast that a visual readout of the measurement results becomes
almost impossible (thanks to the DSP's performance). Hence, we can be happy about SPECTRAN's additional
large bargraph - making such quick level changes still very readable after all. Also, the HOLD mode can
now unleash its full potential.
Should you always have looked for a tool to quickly measure the signal maximum of a specific frequency
when doing EMC measurements, here it is.
- The power flux density display now shows a superscript 2 (²) instead of the old-fashioned "^2".
- The DECT analyzer has been greatly enhanced. By pressing the DECT key (0) several times,
all 10 DECT channels can now be analysed SEPERATELY (display will show "DECT 0-9") according to
You can quickly recognize on which of the 10 channels transmission is currently taking place. Also,
the continuous automatic channel changes of the DECT carrier is now nicely visible.
This seperation of channels is especially practical in AUDIO mode.
However, a very special feature is the AUTOMATICALLY-CHANGE-DECT-CHANNEL-MODE (DECT Auto-Rotate),
which will be automatically activated after first pressing the DECT (0) key. In this mode, all
10 channels are PERMANENTLY measured and displayed in sequence. Thus, you will never miss a channel
change, and you can, for example, quickly measure the total exposure of ALL channels using the HOLD
- In the RBW "FULL" setting, the last "gaps" have been fixed. Thus, you now have a very fast
sweep for LARGE frequency ranges at your disposal.
For example, when pressing the 2 key (sweep from 1-2GHz), change the configuration as follows:
The sweep will now mostly finish after less than a second, even with bigger frequency ranges.
Of course, frequency and level display will now be quite coarse due to the extreme filter bandwidth
of 50MHz. Also, levels must now be above -45dBm to be measurable. However, a great feature
for QUICK orientation.
- The file system has been sped up immensely (for example, significantly faster FACTORY SETUP).
- The 0 key now invokes a new DECT analyzer (TIME DOMAIN MODE for DECT phones)
. Through implementation of a new caching algorithm, screen updates have become
Basically, this mode displays the individual pulses of the DECT signal as well as band usage / band utilisation and the power of the individual pulses.
In this mode, SPECTRAN can establish that a DECT signal constantly changes its frequency. This way, using the
right measurement device, you will find that DECT is, IN CONTRAST to many established "opinions", a pretty
active and complex signal...
- The video filters are now automatically displayed in correspondence with the SPAN or bandwidth.
- In audio mode, the right/left cursor keys will now only move the center frequency by one RBW, giving
you far better control over the audio analysis.
The "step width" can be adjusted easily using the up/down arrow keys, as these - as you know - adjust the RBW.
- The filters (RBWs) have been completely overhauled! The additional "Anti-Aliases Interleave
Sampling Algorithm" now also applies to the 1MHz RBW. Thus, this filter setting will now also
give "crystal clear" display without aliases (with sweep time = 1 or higher, see BETA25). So usually,
the only remaining slight aliases will be visible at 100kHz RBW.
Based on "suggestions", aliases / phantom signals have yet again been reduced by typically 30dB
(1000%). When set to a sweep time of 1 second or longer AND an RBW of 3MHz, an ADDITIONAL
"Anti-Aliases Interleave Sampling Algorithm" will be applied, which virtually eliminates
Obviously, PULSE mode is excluded from this change. Have fun with the now "super clear!" display.
Well, so much for that one ;-))))
- Settings changed in the menus will now be re-displayed when the same menu entry is called again.
On occasion, the default settings were shown instead.
- After leaving the main menu, the unit in use (dBm, V/m, A/m or dBµV) will be shown in the large
info display. As soon as you press a hotkey, the display will switch back to the hotkey's informational
text. Should you, for example, have pressed the hotkey 7 (GSM900), you can "force" a permanent display
of the unit instead of "GSM900" by briefly pressing the menu key twice.
- An error in unit display has been fixed. Thanks to our observant BETA users!
- The sweep time has been sped up DRAMATICALLY compared to previous versions (approx. 100%!!).
This should be an appropriate reaction to the "criticism" of a small manufacturer of broadband
"measurement" devices. Well, so much for this one ;-))))
- The various, factory-preset test signals are now switched off. All remaining "signals" are now
regular background noise of the respective frequency ranges (also recognizable by the fact that
they are still shown even when the antenna is removed).
- New unit V/m, displayed using the large main display (instead of the standard dBm display).
You can activate it using the new menu entry "Unit" in the main menu.
- New unit mA/m, displayed using the large main display (instead of the standard dBm display).
You can activate it using the new menu entry "Unit" in the main menu.
- New unit dBµV, displayed using the large main display (instead of the standard dBm display).
You can activate it using the new menu entry "Unit" in the main menu.
- New intelligent power saving mode (for example, when navigating menus, etc.) to increase battery life.
- When in PULSE mode (shift key), the MODE status field "PEAK" will now be displayed. Thus, the fact
that PULSE mode is active can now also be seen on the display.
- In contrast, when in ADVANCED HOLD mode (dot key), only the MODE status field "HOLD" will be
displayed (used to be PEAK and HOLD).
- When a CALLERR (calibration error during automatic self-test) occurs after switching on the device,
SPECTRAN can now be turned off normally using the on/off key. A calibration error might occur,
for example, when extreme circuit overheating occurs (operation at high ambient temperature or too
high mains voltage level).
- New exposure limits have been added (available directly in exposure limits mode using the
right/left arrow keys). Displayed in %. When exposure limits are exceeded by more than 999.99%, the
display will show
"Salz 1" = the OLD Salzburg precautionary value: 1mW/m² = 1,000µW/m².
"Salz 2" = the NEW Salzburg precautionary value (outdoor areas): 10µW/m² = 0.01mW/m².
"Salz 3" = the NEW Salzburg precautionary value (indoor areas): 1µW/m² = 0.001mW/m².
- The W/m² display now has one more decimal place, enabling display starting at 0.01.
- The W/m² display can now show values as small as 10nW/m² (0.01µW/m²).
- The prefixes n, µ and m are now shown in the UPPER line before the "W/m^2" display. For your
1nW/m² = 0.001µW/m² = 0.000,001mW/m²
- New feature "CUSTOM HOTKEYS": keys 0-9 can now be mapped to SELF-BUILT configurations
(including start & stop frequencies, RBW etc.). Here, program numbers 100 to 109 are mapped to keys
0 to 9. By using the menu entry "Setup" & "Store", your custom configurations can be saved
under these program numbers.
HINT: You can restore the factory setting at any time using "Factor" in the "Setup" menu ;-)
- New feature "REALTIME EXPOSURE DISPLAY": Exposure limit calculation now takes place
IMMEDIATELY and NOT only after a new sweep, giving you an INSTANT display of the exposure limit
when switching from spectrum analysis to exposure limit display (when HOLD is activated).
Also, switching between the exposure limits (using the right/left cursor keys) is now accomplished
in "REALTIME". Thus, you can now instantly compare various exposure limits.
- Demodulator bandwidth for AM & FM has been increased to 3.5kHz, giving you nearly perfect
audio reproduction of modulations etc.
- Automatic correction of LCD contrast when battery life decreases, giving you full display
contrast down to a battery voltage of 6.7V.
- New feature "ADVANCED HOLD": In "Spectrum analysis" mode, the pixel display will not
be erased anymore in "HOLD mode". This allows easy creation of nicely readable daily or long-time
graphs and also usage of the device as an event or LOGGER display!
- Exposure limits mode has been enhanced with a nW/m² (max. 999.9nW/m²) display, allowing the display
of signal levels down to 100pW/m² (0.1nW/m²). ATTENTION: For extremely weak signals, set the marker
level to -90dBm!
- Exposure limits mode has also been enhanced upwards to 100W/m² (max. 99.99W/m²) for measurement of
extremely strong signals.
- AUTO-RANGE has also been enhanced to accomodate the new exposure limits mode ranges above. Thus,
display automatically switches between nW/m² and µW/m² or mW/m² and W/m², respectively.
- ECOLOG institute exposure limits are now integrated as well:
The limit for outdoor areas is 10mW/m² (10,000µW/m²).
For indoor areas, however, the limit is 1mW/m² (1,000µW/m²).
Notice that these limits are ONLY applicable in the frequency range between 80MHz and 3GHz.
ATTENTION: ECOLOG limits need to be measured as RMS (automatically done when using SPECTRAN).
- The very low exposure limits defined by the BNU "Citizen Forum EMC" from 1999 are now
also COMPLETELY integrated:
These are defined as 1µW/m² (1,000nW/m²) for indoor areas (normal living areas).
For sleeping areas, however, the exposure limit is defined as 0.01µW/m² (10nW/m²).
- Marker levels have been extended by a new -90dBm option (-80dBm has been removed in favor
of the new option). This enables you to determine frequencies of even very weak signals.
Accuracy of hotkeys has been drastically improved in the lower level ranges (-65dBm down to the noise
floor) and is now typically +/-2dB starting with the SPECTRAN HF-4040. Furthermore, the complete
frequency range has been re-calibrated accordingly.
Hence, our self-proclaimed goal of +/-3dB typical has been SIGNIFICANTLY exceeded, as additionally the
accuracy ABOVE -65dBm now is as good as +/-1dB typical.
- Bargraph display in exposure limits mode has been made logarithmic. This gives a clearer display of
level changes especially in the lower level ranges.
- Up/down cursor keys have been switched off in exposure limits mode (changing the reference level
in this mode is not necessary and even confusing anyway)
- The key beep should now be far more comfortable (now 3 different tones with drastically reduced volume).
- When in exposure limits mode, the DISPLAY MODE status field now correctly shows "Expos.-Limits" instead
- Order of exposure limits has been changed: The default is now the "Salzburg precautionary values" (display in µW/m² resp. mW/m²) and not, as before, the "ICNIRP limits". Obviously, these limits can still
be recalled using the right/left cursor keys (display in %).
A few words about the Salzburg limits:
The NEW Salzburg precautionary value for OUTDOOR areas is 10µW/m² = 0.01mW/m².
For INDOOR areas, it is 1µW/m² = 0.001mW/m².
The OLD Salzburg precautionary value is 1mW/m² = 1,000µW/m².
- In PEAK HOLD mode, the HIGHEST marker, including frequency and signal level, will now be
FROZEN. This allows switching into exposure limits mode AT ANY TIME during measurement, giving
you the exposure limits of ALL previously established markers (only AFTER a complete sweep has
taken place) WITHOUT having to take another measurement. After returning to
Spectrum mode (2x Enter key), the spectrum display will be erased for a clearer indication of what's
going on. However, the MARKERS will be KEPT.
- Exposure limits mode has been enhanced with a µW/m² (max. 999.9µW/m²) display, allowing display
of signals as low as 100nW/m² (0.1µW/m²).
- Exposure limits mode has been enhanced with a 1W/m² (max. 999.99mW/m² = 1W/m²) display to allow
measurement of very strong signals.
- AUTO RANGE has been integrated into exposure limits mode, which will now automatically switch
between µW/m² and mW/m² depending on signal level.
- New status field "NUMERIC ENTRY": As soon as entry of numbers is possible (various functions
in the main menu), this status field will be swiched on.
- When pressing MENU, the marker blocks will now also show, underneath the START, CENTER and
STOP frequencies, RANGE, MARKER and REFLVL, giving you a better orientation.
- Charge and BAT display have been added. Attention: the BAT display only indicates that the internal
battery is in use - it is NO "low battery" indicator!
- The SHIFT key now toggles PULSE mode, sparing you the burden of navigating through the main menu.
PULSE mode is adequate for signals with unstable frequency or which work with "frequency hopping"
(for example, DECT phones).
- The 10dB attenuator can now be hooked up by setting the menu entry "Atten" to 10dB, allowing you
to measure signals of OVER -20dBm. Thusly, the measurable range has been extended to 0dBm.
- The DECT hotkey (key 0) now sets a fixed RBW (filter) of 1MHz.
- After pressing the DECT hotkey (key 0), PULSE mode is not activated anymore.
- The sweep time of the GSM900 (key 7), GSM1800 (key 8) and UMTS (key 9) hotkeys has been reduced
to 0.1 seconds.
- The sweep time of the DECT hotkey (key 0) has been reduced to 1 second.
- Accuracy of hotkeys is now as good as +/-1dB typical between -65dBm and 0dBm! (Remember
to hook up the 10dB attenuator when measuring over -20dBm).
- When pressing MENU, the marker blocks will automatically display the START, CENTER and STOP
frequencies from left to right for better orientation.
- New exposure limit display in mW/m². This allows easy and accurate comparison with the NEW "Salzburg
precautionary value" (=1mW/m²) in mW/m² as well as %. This display mode already takes into account
the antenna data of the corresponding HyperLOG antenna (complete calibration data).
- Deleting PEAK HOLD is now accomplished by activating and deactivating it (dot key).
- "-120 dBm" display is equivalent to: NO SIGNAL.
- The CLR key now resets the hotkeys 0-9 to their default settings (rescue key for the novice). In addition, the sweep is reset to 0-4GHz.
- In AUDIO ANALYSIS mode, audio bandwidth (RBW) can now be changed around the center frequency
by using the up/down cursor keys. This is very helpful when doing audio analysis or locating modulated
signal sources. This enables you to demodulate very narrow as well as very wide signals around
the center frequency (for example: RBW = FULL for locating all DECT phones AT ONCE). This eliminates
the need for changing settings manually in the main menu.
1.) The DECT hotkey (key 0) currently still uses an RBW (filter) of 3MHz. Significantly better results
can be achieved by using an RBW of 1MHz. Hence, you should change the RBW in the main menu each time you press the
2.) Pages 28 (hardware setup) and 12 (cursor mode) are not yet implemented.
3.) If you press a different hotkey after having pressed the DECT hotkey (key 0), the instrument
automatically switches to PULSE mode. Please revert this setting in the main menu each time you use the DECT hotkey.