Subscriber Loop Portable Test Set

Features & Benefits

Craft Tool for Subscriber Loop Installation and Maintenance

• ISDN Basic Rate
• POTS/CLASS
• P-Phone EBS
• Rugged, Light-Weight, Battery Operation
• ISDN Service Verification
• Call Setup
• Protocol Decode
• Automated BER Testing
• Dual Simultaneous Call Control
• NEBEs, FEBE
• Sealing Current
• P-Phone EBS Verification
• Signaling Channel
• DC Voltage
• Call Appearance and Feature Verification
• Speakerphone Output
• Internet Access Testing
• Personal Video Conferencing
• Telecommuting

Applications

• 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.

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).

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.