Model 4950
10BASE-T1L Channel Emulator with

Integrated Power Monitor and
SCCP Protocol Analyzer

Single Pair Ethernet (SPE) Testing Solution


Telebyte’s Model 4950 offers the world’s first standard-based cable emulator designed for testing Single Pair Ethernet (SPE).

This full duplex link will support power and communications over the same data line connected to devices at the edge of the “smart factory” network. The cost-effective technology provides data and analytics for industrial automation including control systems and cloud applications for remote operation as well as monitoring and management of the entire “intelligent building.” Elevators, HVAC, power, security access, wireless access points, sensors, industrial controls, cameras, robotics, railway and transportation as well as lighting may all be integrated on the enterprise network.

Suitable for Compliance, Safety, and Interoperability Testing.

See this product being used in Telebyte’s Network Topology Diagram

Features Include
Simulation of Single Balanced Pair of Conductors of various cable types and lengths as defined in section 146.7.1 of IEEE 802.3cg-2019; APL Port Profile Specification v1.0, subclause 7.5; IEC 61156-13 section 6.3; and TIA 568.5 section 6.3

Simulation includes:
o Attenuation supports two PHY operational modes (1.0 Vpp or 2.4 Vpp)
o Differential Return Loss
o Link Delay
o DC Resistance
Low Noise Floor of < -165 dBm/Hz
Bandwidth DC to 20 MHz
Integrated Current Monitor, 0 to +/-2.5A
Integrated Voltage Monitor at each end of the link, 0 to +/-60 VDC
Data logging of current and voltage with timestamps every 500ms or 1s
Serial Communication Classification Protocol (SCCP) Analyzer to view register data and logic analyzer view of pulses with timing
Fault Tolerance and Safety Testing with Short Circuits on the differential pair or on signal wires to the Shield (or Chassis Ground) for 75ms (Short Current not to exceed ~3.5A).
Integrated Differential Mode Noise Injection at each end of the cable emulator Side A & B. Wide dynamic range noise output of -70dBm/Hz to -155dBm/Hz when integrating with the Telebyte Model 4975 Universal Noise Generator. Impulsive Noise or Alien Crosstalk.
Internal Power-line Ripple Noise Generation (1kHz to 1MHz) and Injection at each end of the cable emulator, Side A (Power Source) and Side B (Power Load) to test SPoE devices.
Micro-Interrupts from 1ms to 65535ms in 1ms increments to simulate intermittent connections at wire joints (terminal box). Tests Power Over Data Line stability and Signal integrity path with reflections.
Internal AWGN Noise Source on Side A & B with flat Noise outputs from -70dBm/Hz to -150dBm/Hz to test SNR margins
Compliance Testing for Timers to test Maintain Full Voltage Signature for PoDL stability
Supports PoDL Type E Power Class 10-15 Devices w/ 60V DC, 2A, 90Watts and Ethernet-APL Class A, C and 3
1 to 80.5 ohm variable Cable DC resistance emulation in 0.5 ohm increments
Symmetric and Bi-directional emulation
Integrated electronic circuit breaker and Current difference monitor (CDM)
Repeatable, configurable, realistic
Remote Control via telnet or SSH with a command line interface (CLI)
Linux SBC with built-in web server for browser user interface
Made in the USA

Current/Voltage Monitor
The Model 4950 includes an integrated current and voltage monitor at the PSE and PD. In addition, the user may enable data logging to monitor current and voltage over the link for long term thermal or stability testing of Power over Data Line. For safety, the unit opens the cable emulator in the event of over-current error conditions (electronic circuit breaker). Monitor the current difference in the source and return conductors using a Current Difference Monitor (CDM). Log data for Ethernet-APL intrinsically safe devices to ensure limits are maintained for Class A, C and 3.

SCCP Protocol Analyzer
This innovative product includes a Protocol Analyzer for the Serial Communication Classification Protocol (SCCP) to monitor or troubleshoot the half-duplex bi-directional serial data bus for communication between the Master PSE and Slave PD devices. The initialization sequence of reset, presence, write, and read pulses are presented with timestamped information in a tabular or graphical view similar to a logic analyzer. This information is available to the user via a web interface and/or remote commands. The CRC pass/fail criteria, Voltage Info, Power Info, Power Assign and Class Type Info register values may be checked as well.  

Cable Faults
The Model 4950 can verify fault tolerance performance with short circuits on the Single Pair Ethernet link in 75ms increments to determine when the PSE shuts down the output power should a short circuit be detected between the differential pair or a signal wire to ground. The short condition can be placed at the PSE or PD end of the link with normal operation expected after the short circuit is removed.

Spurs mays have up to four inline connections and Trunks may have up to ten inline cable connections. To emulate faulty connections at these terminal points, this product supports mechanical faults called Micro-Interrupts. These may be inserted from 1ms to 65535ms onto the twisted pair link to open a single wire or both wires to emulate a bad wire joint connection.  These micro-cuts may be repeated periodically for long term testing.

If these cable faults are subject to vibration from heavy equipment or HVAC, they may experience impedance discontinuities which affects the signal path with reflections and the DC power to the Powered Device which may cause the link to drop or underperform.

Noise Testing
It is vital to test link performance in noisy conditions such as those found in factory environments with harsh EMI radiated noise. The Model 4950 features integrated differential mode noise injection at each end of the cable emulator and is designed to be used with Telebyte’s 4975 SPE Noise Generator and Analyzer (see separate datasheet) to inject a mixture of noise in the frequency and/or time domain on the data line. This reduces the signal-to-noise margin and validates the data rate and stability of the DUT in the presence of noise.

The Ethernet-APL Data Test Specification v1.0 Receive Packet Error Rate Stress Test is supported by supplying the AWGN and power line ripple voltage to see if the DUT maintains a BER of less than 10-9.

The IEEE 802.3cg Alien Crosstalk Noise Rejection test may be performed with a Gaussian noise distribution at 101 dBm/Hz over 30MHz to see if the DUT maintains a BER of less than 10-10.

Noise Capture
Telebyte’s Model 4975 (see separate datasheet) also supports the signal capture of real-world noise environments on the twisted pair including alien crosstalk, impulse noise, RFI, inductive noise, and the background noise floor. The captured noise can be recorded and played back on the Telebyte noise generator to replicate different noise environments or installations during lab testing.

Cable Emulation
The 4950 simulates variable insertion loss, DC resistance, impedance and delay. There are various cable types existing in different environments and Telebyte supports multiple standards for single twisted pair cable.

Telebyte’s repeatable test solution provides a variety of cable lengths and cable types for both the 1.0 Vpp and 2.4 Vpp transmit amplitude PHY operational modes, each with the applicable low and high insertion loss (attenuation) curves. The 1.0 Vpp (low voltage) is optimal for intrinsically safe applications or relatively low noise environments. For more severe noise environments with older and longer twisted pair cables (with high attenuation), a higher transmit level using 2.4 Vpp is beneficial. Testing both transmit amplitude conditions ensures devices are interoperable in multiple cable plant and EMC environments.

Standards Based Cable Models, Each with an Allowable Cable Length
IEEE 802.3cg section 146.7.1 (1.0 Vpp) 100m, 250m, 500m, 600m, 850m, 1000m
IEEE 802.3cg section 146.7.1 (2.4 Vpp)
Lengths: 50m, 150m, 250m, 350m, 500m, 600m, 750m, 850m, 1000m, 1100m, 1200m*, 1250m*, 1300m*, 1350m*, 1375m*, 1425m*, 1450m*, 1475m*, 1500m*, 1550m*, 1600m*, 1700m*
*Optional cable lengths
 Ethernet-APL Spur Worst Case Cable Model (1.0 Vpp) 200m
 Ethernet-APL Trunk Worst Case Cable Model (2.4 Vpp) 1000m
IEC 61156-13 section 6.3
Lengths: 100m (A-100), 250m (A-250), 400m (A-400), 1000m (A-1000)
TIA 568.5 section 6.3
Lengths: 100m (SP-1-100), 250m (SP-1-250), 400m (SP-1-400), 1000m (SP-1-1000)
Test Setup for 10BASE-T1L Testing


Switching 1 SPE Power Switch Port to32 Powered SPE Devices Over 1 Emulated SPE Channel. Application: Automated Interoperability Testing of Field Powered Devices.