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tProbe™ - T1 E1 VF and Serial Data Analysis
and Emulation Hardware

Portable USB tProbe POD

….the future of T1 E1 VF Data Analysis / Emulation

Overview | Features & Benefits | Basic Software/Features | Loopbacks
Screenshots | Specifications | Application Notes | Buyer's Guide
| T1 E1 Release Notes

Latest T1 E1 Software Ver 11.1.17 is Now Available | Download Now!

Applicatin Development ToolKit for Windows® and Linux Available - click hereto know more

Click to watch tProbe™ Video


GL's new tProbe™ is an enhanced version of our popular USB based T1 E1 VF Analyzer / Emulator. This hardware incorporates all the features of the previous analyzer such as portability, USB interface, remote accessibility, scripting, and a vast collection of optional applications.

GL's tProbe™ also includes ability to add optional boards such as the Datacom Analyzer, and FXO-FXS Simulation boards. The FXO port on tProbe™ allows to simulate a two-wire FXO device such as a telephone or a fax machine. This feature allows you to capture and analyze data from a two-wire telephone line, as well as to generate and transmit analog data onto that two-wire line.

Similarly, the FXS port on tProbe™ emulates a two-wire FXS service such as a telephone wall jack.  This feature allows you to interface with an FXO device such as a telephone.  Server commands allow you to provide standard FXS features such as monitoring for the off-hook line, sending ring signals, and providing dial tone.

pdf User's Guide
pdf Quick Install Guide
pdf Quick Verification Guide
pdf Product Brochure
pdf Frequency Calibration Procedure User Guide
View Presentation
pdf Terminate, Bridge,
Monitor Design-tProbe™
pdf T1 E1 Release Notes
pdf GL Product Lists

GL's tProbe™ Datacom Analyzer is designed for the service installation, verification, and maintenance of Datacom and telecom equipments. It provides a software selectable interface to emulate DTE, DCE and monitor the Datacom lines for both synchronous (sync), and asynchronous (async) modes of operation.

Recently tProbe™ was introduced with the following important enhancements:

  • T1 E1 Pulse Shape, Jitter Measurement Analysis and Jitter Generation

  • tProbe™ FXO and FXS board allows simulating FXO and FXS ports; FXO port to simulate a two-wire FXO device such as a telephone or a fax machine and the FXS port on tProbe™ to emulate a 2-wire FXS service such as a telephone wall jack.

  • tProbe™ Datacom Analyzer board supports V.24, V.35, V.36, RS-449, RS-485, EIA-530 and EIA-530A interfaces and can be configured as DTE or DCE to test Channel Service Unit (CSU) and Data Service Unit (DSU) entities

  • Software selectable T1 or E1 interface along with Drop and Insert

  • Monitor the T1/E1 line conditions such as frame errors, violations, alarms, frequency, power level, and clock (or frame/bit) slips.
  • TDM, ISDN, SS7 – High Density Voice

  • VoIP, Frame Relay, Multilink Frame Relay, PPP and Multilink PPP, HDLC

  • Routing and Bridging emulation over Multi T1/E1 WAN interfaces using MLPPP (Multi Link PPP) and MFR (Multi Link Frame relay) protocols 
  • Call Recording, Generation, and Monitoring for hundreds to thousands of calls in one platform

  • Capable of simulating as well as decoding and demodulating fax calls over T1/E1 lines using Fax Simulator and FaxScan™
  • Windows® and Linux Drivers for Open Source Applications

  • Compatible with Windows® XP , 7 and 8 operating systems and user friendly real-time software
  • Comprehensive Analysis / Emulation of Voice, Data, Fax, Protocol, Analog, and Digital signals, including Echo and Voice Quality testing

  • Improved circuitry for very accurate Digital Line Level measurements

  • Ethernet Interface for future standalone operation

  • Easy calibration

  • Forward thinking hardware design for future daughter board expansion applications

  • Lightweight (1.24 lbs) and small footprint (6.05" x 5.55" x 1.60 ")

  • Switchable Line Level or Microphone input using 3.5 mm or Bantam physical connectors

  • Enhanced VF Drop and VF Insert Capabilities using 3.5mm Balanced (Stereo), or Unbalanced (Mono) physical connections.

  • Includes individual speakers (one speaker per card).

  • The VF Tx and Rx impedance for tProbe™ analyzer supports software selectable 135, 150, 600, or 900 Ohm terminations. Additionally, the VF Rx impedance supports New High Impedance Monitor Termination (>50K Ohms), and external Microphone and Headset (Mic/HS) impedance .

  • VF Tx Gains for tProbe™ analyzer ranges from -12 dB to +59.5 dB in 0.5 dB steps, and VF Rx Gains for tProbe™ analyzer ranges from -63.5 dB to +9 dB in 0.5 dB steps.

GL's offers other popular forms of T1 E1 analysis hardware such as

Capabilities for future applications include -

  • 10/100 Ethernet Interface for standalone embedded applications

  • Standalone Embedded Processor Flash and Platform Flash (SDRAM 512 MByte)

  • Additional Daughter Boards planned include ADSL, Octal T1 E1, T1 E1 Switch, and many more.

Accompanying Basic Software / Features

tProbe™ comes with “basic software applications” for basic testing needs and optional software applications that extend the capability far beyond the most expensive T1 E1 VF and Serial Data testers. All the basic applications and optional applications supported by USB T1 E1 analyzers are also supported by tProbe™. For example, capturing and transmitting an entire raw T1 E1 VF or Serial Data signal simultaneously on two full duplex ports, or performing ISDN emulation, or SS7 analysis, or analyzing echo and voice quality on voiceband channels, to name a few.

A list of all the basic applications and other optional applications (requiring additional licenses) are listed here -

Additional applications supported by tProbe™ are as follows -

Pulse Mask Compliance Testing

In T1 E1 transmission systems, signals are dropped, inserted, and accessed at the electrical level at a point called DSX patch panel or at some similar point. To reliably receive, monitor, or access these signals, they must first conform to a standard that establishes parameters such as pulse width, rise time, amplitude, allowable undershoot and overshoot. If the pulse meets the pulse mask, then a properly designed receiver should be able to decode the bits transmitted.

GL's tProbe™ provides pulse mask compliance testing using Pulse Mask Display for both T1 and E1 applications. Software has been developed to determine if the pulse shape fits within a "pulse mask" as specified by standards ITU G.703 and ANSI T1.102-1993. The software is available in both visual and tabular formats. Tabular formats are convenient for automation and scripted test environments.

For more details, please click here

Jitter Measurement

Jitter along with wander and frequency drift are major impairments of clocks in synchronous systems. Jitter is the time discrepancy between the time of arrival of a clock pulse and its theoretical arrival time. GL's Jitter Measurement module allows evaluation of jitter on either a tick-by-tick or a cumulative basis. Cumulative jitter is of primary importance as network equipment must cope with the cumulative jitter by the use of appropriately sized “jitter buffers”. Tick-by-tick measurements provide instantaneous jitter.

For more details, please click here

Jitter Generation

This application allows the user to generate a jittered output T1 E1 signal with user-selected jitter frequency and amplitude. It is suitable for testing jitter tolerance and compliance with standards such as G.823. In conjunction with GL's Jitter Measurement application, Jitter Generation may also be used to test jitter transfer.

For more details, please click here


tProbe™ supports Normal (no cross-port), Cross-port Through, and Cross-port Transmit loopbacks.

Cross-port Through Loopback

Cross-port Through Loopback

This mode is similar to the standard Outward Loopback except that the signal received on Card 1 (Port 1) is transmitted out onto Card 2 (Port 2). Likewise the signal received on Card 2 (Port 2) is transmitted out onto Card 1 (Port 1). This feature allows monitoring T1/E1 lines in-line while still being protected from loss of power to the board. This mode is effected entirely thru relays and eliminates complex cabling.

Cross-port Transmit Mode Loopback

Cross-port Transmit Mode Loopback

In this Mode, the data that would normally be transmitted on Card 1 (Port 1) is diverted and transmitted on Card 2 (Port 2) and the data that would normally be transmitted on Card 2 (Port 2) is diverted and transmitted on Card 1 (Port 1). The receive paths are completely unaffected. This mode is particularly useful for Drop and Insert and Error Injection applications in which the board analyzes and may insert traffic running between two pieces of T1/E1 equipment. This feature also eliminates complex cabling.


Physical Interface

USB Connector

(1) USB TYPE B Jack

Ethernet Connector

(1) RJ-45 10/100 Ethernet Jack

T1/E1 Connectors

(2) RJ-48c Jacks 

Audio Connectors

(4) 3.5 mm Balanced (Stereo) or unbalanced (Mono) Audio Jacks (TX & RX)

External Clock Connector

(1) MCX Coaxial Jack

External Power Connector

(1) Coaxial DC Power Jack (mates with 5.5mm x 2.1mm coaxial plug)

Optional Boards

2-Wire Daughter Board (One FXO, One FXS)

FXO - RJ-11
2W Call/Answer
Caller ID
T1 to 2W FXO Drop
2W FXO Insert to T1
PC to 2W FXO Drop
2W FXO Insert to PC
FXS - RJ-11
Ring Voltage
Battery Voltage Generation
T1 to 2W FXS Drop
2W FXS Insert to T1
PC to 2W FXS Drop
2W FXS Insert to PC

Datacom Daughter Board

Dual DB25 Connectors Support:
RS-449/V.36 /V.10/V.11

External Power Requirements

Power Adapter Requirements

+5V @ 2A Max Power to the Center Ring

T1/E1 Line Interface

Framing Formats

Unframed, D4 (T1) , ESF(T1), CAS(E1), FAS(E1), CRC4
Hardware Compliant: SLC96, T1ESF ZBTSI

Line Code format

AMI, B8ZS (T1) or HDB3 (E1)

Internal Clock Specification

Standard: ± 3ppm  Optional: ± 1ppm

Output Clock Source

Internal (± 1 ppm or 3 ppm), Recovered, External Clock

T1 Output Level

T1: 3.0V Base to Peak Selectable 0-655Ft Pulse Equalization Setting; Tx Capability - DSX-1 Outputs (to 655 feet)

E1 Output Level

E1: 3.0V ±  0.3V Base to Peak

Input Level

75 mV to 6V base to peak or -30 dBsx to -6 dBsx

Line Built Out Selections

0dB, -7.5dB, -15dB, -22.5dB for T1 only


Normal (Outward and Inward)
Cross-Port Transmit Loopback
Cross-Port Through Loopback


T1/E1 Interface Hardware Compliance

- ANSI: T1.403.1995, T1.231-1993, T1.408
- AT&T: TR54016, TR62411
- ITU: G.703, G.704, G.706, G.736, G.775,  G.823, G.932, I.431, O.151, Q.161
- ITU-T: Recommendation I.432-03/93 B-ISDN User-Network Interface-Physical Layer Spec
- ETSI: ETS 300 011, ETS 300 166, ETS 300 233, CTR12, CRT4
- Japanese: JTG.703, JTI.431, JJ-20.11 (CMI Coding Only)

BERT Pattern Generation

Pseudorandom patterns: (63) 26-1, (511) 29-1, (2047) 211-1, (32767) 215-1, (1048575) 220-1, (8388607) 223-1, QRSS.
Hardware Compliant: T1 In-Band Loop Code Generation and Detection
Fixed patterns: All Ones, All Zeros, 1:1, 1:7, 3 in 24, User Defined 24- Bits
Hardware Compliant: User pattern of up to 32 bits in length

Alarm Insertion

Blue, Yellow, Remote, Distant Multiframe
Hardware Compliant:
Bit 7 Zero Suppression
D4 Yellow: 1 in S bit of frame 12
Receive Carrier Loss: 0’s for 2047 or 255 bits (For E1 only)

Error Insertion

BPV, Bit Error, Frame Error, CRC Errors, Burst Frames, Fixed Error Rate, Random Error Rate, auto logic from 10-2 to 10-9 for selectable 56K or 64Kps channels.

Drop and Insert

Any contiguous set of digital timeslots and/or audio input

Facility Data Link

T1 ESF Mode: Transmit/Receive Messages, Bit-Oriented Messages, and Files.

Zero Suppression

B7 Stuffing, Transparent, & B8ZS (T1)


Robbed-Bit or Clear Channel

Frequency Offset

T1: +/- 615Hz

E1: +/- 615Hz


Input Impedance

100 ohms for Terminate and Monitor (T1)
120 ohms for Terminate and Monitor (E1)
> 1K ohms for Bridge


Terminate, Monitor, Bridge

T1 Input Frequency

1.544MHz ± 20KHz

E1 Input Frequency

2.048Mhz ± 20KHz

Frequency Measurement

± 1ppm

Error Detection

Frame Error, CRC Error, BPV Error, Logic Error, Frame Alignment Error
Hardware Compliant:
* 10 or 24 bits for sync time
* 2/4, 2/5, or 2/6 frame bit in error frame select
* Frame error bit corruption for 1 or 3 frame bits
* E-Bit Error
* Line Code Violation

Alarm Detection

T1 - D4 Yellow Alarm, ESF Yellow Alarm
Yellow Alarm (B2 Suppressed-2nd MSB)
Yellow Alarm (S-Bit)
Yellow Alarm (00FF in FDL)
Blue Alarm (Framed or Unframed All Ones)
E1 - Remote Alarm
Distant MultiFrame Alarm
Signaling All Ones
Unframed All Ones
Hardware Compliant: J1 Yellow Alarm

Intrinsic Jitter

Meets Jitter Tolerance:
Meets AT&T TR 62411 (Dec. 90)
Meets ITU-T G.823
Jitter Transfer:
Meets AT&T TR 62411 (Dec. 90)

Input Range

T1: Terminate, 0 to 36dB (Long Haul), DSX Monitor, Bridge
Hardware Compliant: Terminate, 0 to 15dB (Limited Long Haul), DSX Monitor 20dB, 26dB, 32dB
E1: Terminate, 0 to 43dB (Long Haul), DSX  Monitor, Bridge
Hardware Compliant: Terminate, 0 to 13dB (Short Haul), DSX Monitor 20dB, 26dB, 32dB

Display and Logging


Bit Errors, Bit Error Rate, Error Seconds, Error Free Seconds, %EFS, Severely Error Seconds, % SES, Degraded Minutes, %Dmin, Loss Pattern Sync Count, Loss of Sync Seconds, Available Seconds, %Available Seconds, Unavailable Seconds, Bipolar Violations, BPV Rate, BPV Seconds, BPV Free Seconds, Frame Errors, FE Rate, FE Seconds, FE Free Seconds, with Detailed logging into disk file.


Resync In Progress, Loss of Signal, Blue Alarm, Change of Frame Alignment, Bipolar Violation, Frame Error, Carrier Loss, Yellow Alarm, Out of Frame Events Counter, Error Super frame Counter, Bipolar Violations, Remote Alarm, Distant Multiframe Alarm, Signaling All Ones, CAS Multiframe Error, CRC4 Error.

VF Drop and Insert
Refer to VF Drop and Insert Capabilities webpage for more details.

Rx Termination

High Impedance (>50K Ohms) for Non-Intrusive Testing
Software selectable 135, 150, 600, 900 Ohms for Intrusive Testing
Provision for external Microphone (Mic/HS) on VF ports connection
External Microphone and Headset (Mic/HS) on VF ports connection

Tx Termination

135, 150, 600, 900 Ohms

Sampling Rates


Datawidth (bits)

 Supports 8, 16, 20, 24, 32 Bit Data

VF Tx Gains

Supports -12 dB to +59 dB in 0.5dB Steps Gain (0.1 dB steps can also be accommodated in tProbe™)

VF Rx Gains

Supports -63.5 dB to +9 dB in 0.5dB Steps Attenuation (0.1 dB steps can also be accommodated in tProbe™)


(4) 3.5 mm Balanced (Stereo) or Unbalanced (Mono) Audio Jacks (TX & RX)

Physical Dimensions


6.05 inches (153.67mm) (L)
5.55 inches (141.224mm) (W)
1.60 inches (40.64mm)  (H)


1.24 lbs. (0.56 kg)

Coming Soon

Main Board Features

Standalone Platform Flash
SDRAM – 512MByte
Embedded Processor Flash

* Specifications subject to change without notice.

Application Notes

Buyer's Guide

Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide, which the software will be running on. Therefore, XX can either be ETA or EEA (Octal/Quad Boards), PTA or PEA (tProbe Units), UTA or UEA (USB Units), HUT or HUE (Universal Cards), and HDT or HDE (HD cards) depending upon the hardware.

Item No. Item Description


tProbe™ T1 E1 Base Unit




tProbe™ Basic T1 Software

tProbe™ Basic E1 Software

High Stability Internal Clock Option

  Related Hardware





w/ Optional Datacom Analyzer Board for RS-232, RS-449, RS-422, RS-423, EIA-530, V.35 Interfaces

w/ 2Wire FXO and FXS Optional Board for simulating FXO and FXS ports

QuadXpress T1E1 Main Board
(Quad Port– requires additional licenses)
OctalXpress T1E1 Main Board plus Daughter Board (Octal Port– requires additional licenses)

Basic Software for T1 (zero dollar, but required with appropriate licenses)
Basic Software for E1 (zero dollar, but required with appropriate licenses)

HD Universal Dual T1/E1 Card
HD Universal Card Basic T1 Software
HD Universal Card Basic E1 Software
High Stability Internal Clock Option
Dual Laptop T1/E1 Hardware USB Base Unit
Basic Laptop T1 Software
Basic Laptop E1 Software
High Stability Internal Clock Option
Dual T1 E1 Express (PCIe) Boards (requires additional licenses)
Dual T1 E1 Express Card Basic T1 Software (includes xx600, xx605)
Dual T1 E1 Express Card Basic E1 Software (includes xx600, xx605)
  Related Software
  For Buyer’s Guide details on related software for tProbe, refer to this webpage.

*Specifications are subjected to change

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