Micro Seven, Inc.

LS300 Advanced Telephone line simulator


Advanced Telephone Line Simulator, model LS300, provides a 2-line simulated telephone-line station with displays of dialed numbers, loop voltage, and loop current in a 19-inch rack-mount configuration. The loop voltage and loop current are adjustable for wide ranges by panel-mounted potentiometers. Ring signal frequency and amplitude and random noise amplitude are adjustable by potentiometers through front panel holes. Random noise and frequency attenuation characteristics are enabled or disabled by dialing unique numbers to test telecommunication products for their frequency responses. It also contains an RMS voltmeter for measurement of DTMF signal amplitude, signal levels, and ring signal amplitude. The Caller-ID option provides caller-ID signals that transmit caller's names, directory numbers, date, time, and private/out-of-area information. Alarm panel testing option is also available.


Models LS300, Advanced Telephone Line Simulator



Various models: LS300-1, LS300 with Caller-ID & RS232C interface

LS300-2, basic LS300

LS300-3, LS300 with true Line Impairment Options

LS300-4, LS300 with true Line Impairment Option and Caller-ID & RS232C Interface

LS300-5, LS300 with alarm panel testing option and true Line Impairment Option and Caller-ID & RS232C Interface

FOB: Hillsboro, OR

Term: VISA/MC, COD, or net30(for credit-approved customers)


- Testing of Ademco contact-ID alarm panels under the worst case telephone line conditions

- Display of dialed numbers, loop current, and loop (line) voltage

- Easy adjustment for loop current and loop voltage

- Adjustable Ring Signal Frequency, ring signal amplitude and random noise level

- Programming of frequency attenuation characteristics and inserting random noise

- Ring Switch to generate ring signal at line 2 without dialing a number

- 16 digit-dialing or user programmable phone numbers

- Dual frequency call progress tones

- Distinctive ringing features (total four different ringing patterns)

- RMS voltage display

- Caller-ID generation (option)


Application and benefit

- Useful tool to test telecommunication products for many criteria including dial numbers, loop current responses, and loop voltage responses.

- Measurement of DTMF amplitude level, or signal amplitude by using RMS option.

- Testing for frequency responses

- Testing distinctive ringing receiver

- Testing Caller-ID receivers (Caller-ID Option)



Front Panel Displays and Controls

Numerical LED displays: loop current, loop voltage, and dialed number (or RMS voltage display)

4x7 segment LED (total 20 segments), hexadecimal, 0.3 inches character height.

Loop current for Line 2: 2-digits, 20-60 ma +/- 1 ma

Loop voltage (line voltage across tip and ring) for line 2: 2-digits, 20-60 V, +/- 1 V

Dialed Number for line 1 and line 2: 4-digits with leading zeros blanked


LED Indicators:

Power: green LED

Ring Indicator for Line 2: Red LED is on when ring signal is applied at line 2.

OH/BUSY LED for line 1 and line 2: Red LED to indicate presence of loop current. When high current is drawn during the ring cycle, the LED is also turned on dimly.


Panel-mount Potentiometers:

To adjust loop current for line 2 within a range of 20-60 ma and loop voltage for line 2 within a range of 20-60V. The loop voltage may be measured as line voltage at line 2 with on-hook condition.


Potentiometers adjustment through front panel holes:

Noise adjustment: Random noise is inserted to both line 1 and line 2 when frequency attenuation mode is enabled after dialing 0 0 and line number.

Ring signal amplitude adjustment: 40 to 100 VRMS

Ring signal frequency adjustment: 16 to 68 HZ

Transmit power adjust potentiometers: 0 to 40 dB

Note: The minimum insertion loss between line 1 and 2 is 2 dB.



Ring Switch to start a ring cycle at line 2. When it is pushed again, it stops the cycle.

Aux. Switch: It indicates that the RMS display of loop voltage is selected.


RS232 interface:

Programmable features: telephone number, line impairment option, call progress tones, disconnect signal, PBX mode, caller-ID etc. The control software for MSDOS is provided.


Telephone Numbers: primary telephone number for 1 or 2 as a factory default condition.

Secondary telephone number: (programmable telephone number)+(line number)

For example, 18005551211 for line 1 and 18005551212 for line 2.

DTMF dialing: -13 dBm to +5 dBm per a frequency, and no more than 4 dBm difference between frequencies.

DTMF dialing detection time: 45 ms

Pulse dialing: Break period: 45 to 75 ms (60 ms nominal)
Make period: 30 to 60 ms (40 ms nominal)


Line characteristics:

Input impedance at 1 kHz: 600 ohms +/- 5%
Signal Range: -45 to +5 dBm
Bandwidth noise: 2mV P-P max. (-60 dBm) (full bandwidth mode)
Signal Bandwidth: 150 HZ to 5 kHz (full bandwidth mode)

Frequency attenuation characteristics for both signal directions:

-Dial 0 0 to get the frequency attenuation characteristics and random noise enabled.
Relative Attenuation Characteristics to 1 kHz:
+12 dB @ 300 HZ
+ 8 dB @ 500 HZ
+ 8 dB @ 2500 HZ
+12 dB @ 3000 HZ

-Dial 0 9 to return to full bandwidth mode.

Off-hook impedance requirement:

400 ohms maximum DC, 600 ohms nominal AC

Disconnect Signal:

There is interruption of loop current for 0.5 sec when the other line terminates a call. For example: assuming that the line 1 and 2 are connected. The loop current of line 1 is interrupted for 0.5 sec when the line 2 hangs up.


Dual Frequency Call Progress tones:

Dial Tone: 350 Hz + 440 HZ continuous.
Ring-back Tone: 440 Hz+480 Hz, 2 sec ON/4 sec OFF.
Busy Tone: 480 Hz + 620 Hz, 0.5 sec ON/0.5 sec OFF.
Signal Power: - 20 dBm nominal.


Ring Signal:

Amplitude: 40 to 90 VRMS sine wave
Frequency: 16 to 68 HZ
Interval: nominally 2 sec ON/4 sec OFF
Distinctive Ring Features: User programmable for four different ringing patterns.
It is set as 2 sec on/4 sec off as a power-up default condition.

Transmit Power Adjustment Potentiometers:

It attenuates the signal output from the line between 0 to -40 dB range.

RMS Voltage Measurement

RMS Measurement Mode is entered by pushing Aux. Switch once to display AC RMS voltage of line voltage at line 2. It goes back to the normal DC voltage display by pushing the Aux. Switch again.

Caller-ID Option:

Caller-ID Option simulates Caller-ID signals that are provided by telephone companies. It transmits date, time, name and calling line's phone numbers. It supports both single and multiple message formats for U.S. and Canada. The privacy or out-of-area code instead of transmitting phone numbers and names is also enabled. It contains a battery-backed real-time clock, and most of caller-ID parameters are programmable by entering special DTMF codes. It is also programmable by RS232C interface.

Line Input Jacks: USOC-RJ11-C, standard modular phone jacks

Power: Requirement: 100-130 VAC, 50/60 HZ
Note: 230V power unit is also available.

Fuse: .3A, 3AG, SLOBLO


Dimensions: 19"W x 3.5" H x 13" L

Weight: 13 lbs.

Environmental: Operating temperature: 0 to 45 degree C Humidity: 85% RH at 45 degree C

Warranty/Service: Six month limited warranty. Service is performed at the factory, usually within 10 working days.


LS300-5, which includes alarm receiver, model CT10, is shown in the above picture.


Micro Seven, Inc., Hillsboro, OR, U.S.A.