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Subscriber Loop Portable Test Set

CrafTek™ CT100 • Opt. 2A • Opt. 3B

CrafTek™ CT100 • Opt. 2A • Opt. 3B

Features & Benefits

Craft Tool for Subscriber Loop Installation and Maintenance
  • ISDN Basic Rate
  • P-Phone EBS
  • Rugged, Light-Weight, Battery Operation
  • ISDN Service Verification
  • Call Setup
  • Protocol Decode
  • Automated BER Testing
  • Dual Simultaneous Call Control
  • Sealing Current
  • P-Phone EBS Verification
  • Signaling Channel
  • DC Voltage
  • Call Appearance and Feature Verification
  • Speakerphone Output
  • Internet Access Testing
  • Personal Video Conferencing
  • Telecommuting


  • Telephony
  • ISDN Performance
  • PC Communication

Subscriber Loop Portable Test Set CrafTek CT100

The CrafTek Subscriber Loop Test Set is designed to meet the changing needs of the telephony craftsperson, with flexibility to handle rapidly evolving and increasingly sophisticated digital technologies.

The CrafTek CT100 allows today's work force to troubleshoot problems in the subscriber loop, without retraining. An easy-to-understand human interface, backed by a self-prompting, plain English display featuring extensive error messaging, allows the instrument to be put to work within minutes.

As the craftperson's primary installation and maintenance tool, the CrafTek CT100 meets high standards for ruggedness, portability, and reliability. In addition to traditional analog POTS service, the portable test set provides comprehensive ISDN and P-Phone measurements and indicators for rapid performance verification and fault diagnosis. New services can be provided more efficiently, customer downtime minimized, and problems quickly resolved using the CrafTek CT100 servicing solution.


The CrafTek CT100's Home screen displays the current instrument operating mode. The word "LOG" indicates that data logging has been enabled.

CrafTek CT100 RS-232 Serial Interface Troubleshooting Opt. 2A

The CrafTek CT100's RS-232 interface (Opt. 2A) allows the user to connect an external device to the portable test set over a serial interface. This option provides for two capabilities when in use. The first is data sourcing, providing enhanced testing of ISDN D-channel packet data capabilities. The other capability is data logging, allowing the user to record results of installation and troubleshooting tasks.

Packet Data Testing Over RS-232

In the data sourcing mode, the RS-232 interface allows the user to connect a terminal and initiate X.25 packet-switched data calls over an ISDN data channel. This mode is useful when accessing packet gateways requiring more than a simple phone number (e.g., passwords) or to more fully verify D-channel user applications.

The operator connects their computer's serial interface to the unit's auxiliary jack (DB25-to-RJ45 adapters included). A PC communications software package can then be used to send standard Hayes-compatible modem commands to setup and maintain a D-channel packet call.

D-Channel Monitor

In the data logging mode, the user can use the RS-232 port to connect a printer or terminal directly to the unit. Details such as call setup, signaling protocols, and measurement results can be recorded for later analysis. Figures 1 and 2 provide examples of the type of information available when operating in the data logging mode. This mode of operation allows the user to monitor the events that are taking place on the D Channel.

For instance, the CrafTek CT100 might be used to monitor a line over an extended period, recording time-stamped events such as synchronization loss or data transmission errors. A problem call could be documented from call setup to tear-down to trace CPE or switch-related trouble, in the absence of more complex protocol analyzers. Or the technician may simply use the data logging mode to record results of the service verification procedures when on-site.

Easy Installation

The RS-232 interface board is installed in a separate option slot inside of the unit and is accessed through the existing Auxiliary port on the base of the instrument. Hardware kits are available for easy field upgrading of existing instruments. The interface is fully isolated as well, preventing the risk of damage occurring if devices are directly coupled (e.g., ground loops).


Example of ISDN call in progress.


Example of logging block errors.


Example of results from BER test.

Opt. 3B

Northern Telecom's EBS

Enhanced Business Service (otherwise known as "EBS" or "P-Phone") is an analog Centrex offering provided by Northern Telecom (NORTEL). It operates over a single-pair subscriber wire loop which provides for full duplex audio conversations as well as a secondary signaling channel. This secondary channel is a half-duplex, 8-kHz amplitude-shift-keyed signal, which is used to transmit signaling information to and from the NORTEL switch and the CPE. Thus, the craftsperson is faced with a more complex servicing task when deploying and maintaining P-Phone lines.

When configured with the optional EBS interface card, the CrafTek CT100 is capable of emulating an EBS Primary phone set, as well as several types of add-ons. A simple setup menu allows the user to select between a Primary set, select add-on sets (18-, 20- and 36-button) or a "monitor" mode which allows passive monitoring of both voice and signaling channels.

Unlike most EBS test sets on the market today which merely draw dial tone and place calls, the CrafTek portable test set adds crucial measurement and debug capabilities to aid the crafts technician.

In a typical EBS operating mode, the CrafTek CT100 begins in place of the Primary set allowing the user to go off-hook and place calls. Feature keys can be set to emulate setting up multiple call appearances and verifying features such as call forwarding, hold, and release. The unit's LCD display simulates the display unit of the EBS Primary phone, showing such information as the number being dialed, the calling party's number, and other information sent by the CO switch for display.

Powerful Troubleshooting Tool

Several important measurement capabilities are provided to further aid in EBS service verification and troubleshooting.

DC line voltage and polarity can be measured to verify that the voltage found on tip and ring is within operation specifications. (Showing red for reversed, green for correct).

The peak signal level of the 8-kHz secondary channel must also fall within certain parameters for proper signaling between CO and CPE. The measurement is made in terms of dB loss, with zero dB being calibrated to the nominal signal level found at the central office. Signal loss due to loop imperfections or extended length from the CO, as well as performance margin of the existing loop, can be quickly analyzed using this measurement.

Another useful tool for troubleshooting is to monitor messages that are being sent over the signaling channel. The CrafTek CT100 captures and displays in real time these hex data message elements being sent from the CO switch. One display allows the information to be viewed in raw hex data form (with the most recent 14 message elements displayed on screen). Another display offers the same hex data in a decoded format (for example a hex value of "48" decoded is "Save Indicator Reset"). A buffer also retains the most recent 99 decoded message elements received for review.



Display - Supertwist Liquid Crystal (LCD), Backlit.

User Interface - Easy-to-use menus with extensive user prompts and error messages through a 4-line × 20 character LCD.

Easy Configuration - Provides a step-by-step procedure for instrument setup.

Easy View - Provides a convenient way to review CrafTek status and settings.

Power Supply - Rechargeable NiCd battery pack. Alkaline "C" cells or 120 V AC with adapter. "Low Battery" and "Charging" indicators are on the LCD. Automatic shutoff.

Interface Ports - Four RJ45-type jacks (LINE, S/T(NT1), S/T(TE), Auxiliary).

Speed Dial - Storage for ten numbers (up to 22 digits per number) plus last number redial.


Dial Modes - DTMF, Pulse

Functions - Meets monitor mode, talk mode, and acoustic response requirements as specified in Bellcore TR-TSY-000344

Measurements - Polarity

CLASS - Support of "Customized Local Access Signaling Services" (calling line ID, calling name; with buffer)


TE Compatibility - AT&T terminal equipment, NORTEL terminal equipment, and National ISDN equipment.

Software Generics - Currently compatible with AT&T software generics up to and including 5E9, NORTEL DMS-100 up to and including BCS-36; National ISDN-1 (AT&T, NORTEL, Siemens).

TE Functions - Provides basic voice services plus redirect. Supports BRITL (Basic Rate Interface Test Line). Supports D-channel X.25 Packet Data testing. Supports call setup for multiple bearer services (speech, 3.1-kHz audio, 64-Kbps and 56-Kbps circuit switched data). Allows both B channels to be active simultaneously.

S/T Interface - Complies with T1.605-1991 ISDN Basic Rate Interface Specifications.

"T" Terminations - Selectable: Bridged, 100 ohm.

"T" Pad Attenuation - Range: 0 to 15 dB; resolution: 1 dB.

"T" Synchronization - LED: red = no sync; orange = sync, not activated; green = sync, activated.

Hook LED - Red = awaiting dial tone; orange = negative acknowledgement; green = dial tone/active call.


AMI Interface (Opt. 1B) - Meets specifications defined in AT&T Technical Reference 801-802-100 for AMI Loop Interface.

2B1Q Interface - Meets specifications defined in ANSI T1.601-1992 Standard. Complies with all 15 defined ANSI "U" loops. Supports Quiet and Insertion Loss modes (AC/DC Triggers).

S/T Terminations - Selectable: Bridged, 100 ohm, 50 ohm.

"U" Pad Attenuation - Range: 0 to 42 dB; resolution: 1 dB.

"U" Synchronization - LED: red = no sync; orange = sync, not transparent; green = sync, transparent.

ISDN Measurement and Indicators

Block Errors (NEBE/FEBE) - Total errors, errored seconds, selectable elapsed time

Sealing Current - Presence with polarity indication

2B1Q Battery - Presence with polarity indication

Local Power - Presence with polarity indication

S/T Power Sources 1, 2, and 3 - Presence with polarity indication

TE Receive Level - Range: -9 dB to +3 dB; Resolution 0.5 dB

Indicators on LCD - INFO ("F" and "G") states, LAPD and CALL states, B channel, current call (A or B), TEI number, ANI number, CAUSE and EOC messages, sealing current

BER Testing - Provides 64-Kbps and 56-Kbps BER testing on either B channel or both B channels simultaneously

B-Channel Loopback - Allows either B channel to be placed on loopback mode

D Channel - Provides X.25 packet data testing, including integrated "fox" message transmission

40-kHz Test Tone Generation - Output: 0 dBm ±2 dB

P-Phone (EBS)

P-Phone Interface (Opt. 3B) - Provides support for NORTEL "Enhanced Business Service", including phone emulation for primary set, add-on sets, and Monitor mode (allows monitoring of voice and signaling channels); 2 × 16 message display.

P-Phone Measurements - DC Voltage and Polarity; peak signal level of 8-kHz signaling channel; signaling message elements (hex and decoded displays, with buffer).

RS-232 Serial Port

RS-232 Interface (Opt. 2A) - Provides an RS-232 interface for D-channel packet data sourcing. Also supports data logging to a printer or terminal (ISDN protocols; measurements; EBS signaling; CLASS messages).


Physical Environment - Designed for rugged field use: Weather, moisture, dust, and shock resistant.

Physical Characteristics
















Net w/NiCd battery pack


3 lbs. 6 oz.

Safety - UL1244, CSA231