| Developers of telephony-related products often
need to test their products using ISDN or T1 circuits. Also, exhibitors at
communications-related trade shows often need to rent ISDN or T1 circuits
to be able to demonstrate their products to attendees. Unfortunately, the
costs of renting a T1 or ISDN circuit at a trade show or buying a test T1
or ISDN line for usage in a lab environment can be prohibitive. Coming to
the rescue is the Gordon Kapes System 930 Telephony Simulator, which gives
the choice of ISDN PRI protocols, robbed bit T1 protocols, or both. Two
1.544 Mbps digital interfaces permit an "end-to-end" simulation
of a PSTN/VPN. Thus, you can simulate telephone calls transmitting across
a digital telephone network, testing applications connected at either end.
INSTALLATION
The front of the 930 features an on/off physical toggle switch, three
indicator lights, and two synchronization LEDs for each interface. After
removing the unit's two front covers we discovered three upgrade slots and
a removable motherboard. We should also mention that a representative from
Gordon Kapes visited our offices to swap out some socket chips for some
new ones containing the latest and greatest firmware. He could have sent
us the chips for us to install (it's easy enough to do), however, he
wanted to meet the TMC Labs engineers as well as demo the latest software.
We've had the System 930 in our labs for nearly a year now, so it's
already been installed for quite some time. However, to give you a feel
for how simple it is to install the System 930, we disconnected all the
wiring and connections to see how quickly we could get it back up and
running. To start with, we connected the included power supply box (about
the size of two bricks) to the wall outlet, which is used to convert the
power to 48VDC required by the System 930. On the other side of the power
supply was another cable with a plastic snap-on module on the end that
fits snuggly onto the main System 930 unit.
Next, we connected a serial cable from the System 930's serial port to
a PC with HyperTerminal installed. Finally, we plugged in a single analog
phone into Analog Port 1. If we wished, we could have also connected
amphenol connectors to one or both of the System 930's analog ports, which
support up to 32 analog ports. Finally, we connected one end of an RJ45
network wire into one of the System 930's two RJ48 ports and the other end
we connected to the second RJ48 port, creating a loop-back test. We
flipped the switch to turn it on and it worked. That's it. We were done
installing the unit in about three minutes!
We should point out that since the 930 is a black-box device, there is
no software to install or configure in the traditional sense. All that is
required is a PC with Windows' built-in HyperTerminal program for
configuring, controlling, and monitoring the 930.
DOCUMENTATION
The documentation consisted of an online help accessed via the F1 key, as
well as two separate manuals for E1 and T1/ISDN-PRI. We examined the
manuals, which are in Acrobat form, and were pleased with their
organization. Screenshots of the menus (within a terminal emulator) are
included, and certainly aided in learning the particular features. On the
negative side, there was no index or table of contents, which made
searches longer than they should have been.
FEATURES
The System 930 can emulate the network or user side of robbed bit T1, NI-2
compliant ISDN-PRI, GR-303 CSC, and NFAS (non-facility associated
signaling) using T1 framing. In addition, 4ESS, 5ESS, DMS100/250, and GTD5
switches can be emulated. Q.931 public or private networking protocols as
well as private or proprietary networking protocols that employ
out-of-band progress tones can also be supported.
Important in a testing environment, the 930's protocol analyzer
displays ISDN messages sent to or received from either digital interface.
Layer 1, 2, and 3 information is displayed. Robbed bit T1
protocol-equipped System 930s display A-B bit status and DNIS DTMF digits
received.
System configuration options include:
- Analog port configuration: Extension parameters, ACD assignment,
voice coder compressions (64K G.711 mu-law or a-law), choice of loop
or ground start, and alert failure types. The remaining screens under
this option let you control the actual extensions for 32 channels.
- Recorder/announcer: The simplest menu of the entire system. Its
features are used for recording the two system prompts, which are
useful for troubleshooting telephony products.
- Inbound match configuration: Up to 48 extensions can be programmed
to synchronize with different ACD groups. These matches can also be
set on a per-interface basis.
- Analog port dialing configuration: This screen lets you choose items
like access digits, digit timeouts, and dialing methods (overlap or
en-block).
- Outbound call configuration: The same options as inbound match
configuration.
- ACD configuration: Choices include query depth, queue action,
overflow action, and hunt method.
- Redirect configuration: Choose the prefix number, inbound number,
type of number, action, and destination.
- Audio monitor configuration: Output on/off, mode, source, DCN/Port
setup.
- Security configuration: Login, password, VT-100 compatibility,
automatic logoff, inactivity timeout.
- Call status: Displays current call data, called/caller number modes,
connect resources.
- Transmission status: Synchronization status, transmit/receive slips,
alarms, etc.
OPERATIONAL TESTING
The System 930 interface utilizes any VT100-compatible terminal emulator
for navigation. We chose to use HyperTerminal which comes included with
Windows. After configuring HyperTerminal for 9600 bps, 8 bits, no parity,
1 stop bit, we connected to the 930 and were prompted with the main menu,
which consisted of a list of 22 enumerated choices. After selecting any
one of the menu choices, the screen would refresh with the sub-menu's list
of available menu selections. We could drill even further down into the
sub-menu by selecting another available option, or we also could press
<ESC> to return to the main menu, or press <F3> or <F4>
representing "forward" and "back" one menu (similar to
a Web browser). An indicator in the screen's upper right corner reminds
you of which screen you're currently viewing, and an asterisk denotes the
default selection for each menu option. At any time, we could press
<F1> to bring up the help menu for the particular screen we were
viewing. Although the online help menu was simple text, which we had to
scroll through to find what we were looking for, it was quite useful.
One nice feature we liked during our testing was the ability to quickly
toggle various testing parameters. For instance, with the simple press of
the spacebar when on the "sync source" field, we were able to
toggle between using an internal or external clock. Another nice feature
was ability to view the "bits" of each channel
"real-time" on the screen. With so many nested submenus it's
easy to forget which parameter you changed. Simply by typing
"factory" you can set the 930 back to factory defaults. Another
nice feature was that the 930 auto-sensed when we created a loop-back
test, when we connected an RJ-45 cable from the first interface port
directly to the second interface port. It automatically switched one
interface to "network side" and the other to "user
side".
Called number information, or DTMF DNIS, is used to route incoming
digital call traffic to the other digital interface, or to convert and
route calls to analog, loop-start telephone ports (either individually or
to ACD-like port groups). The 930 includes eight analog telephone ports as
standard equipment. Additional telephone ports, to a maximum of 32, are
optional. Instead of connecting calls to analog ports, incoming calls can
be connected to the system's two integrated solid-state voice announcers.
Voice messages up to 20 seconds in length can be recorded and stored for
future playback.
We're Going To Pump You Up
The System 930 is more than just a simulator of T1, E1, and ISDN
protocols -- it's also a bulk call generator capable of
"pumping" calls into any telephony product you connect to it.
The System 930's internal "bulk" call generator can be
programmed to initiate up to 48/60 (T1/E1) simultaneous calls on a
repetitive basis. Call generator scripts can be created to simulate
"real-world" events. For instance, a sample script could consist
of waiting for the called party to answer, then send DTMF or progress
tones, play a message, record a message, and then disconnect. Another
example script: "d123;v1;h" simply dials DTMF tones 123, then
plays voice prompt 1, and then it hangs up. Silence detection and voice
detection within scripts are also supported.
Capture This
The 930's data capture utility is quite useful in a test environment.
The data capture utility allows you to select Layer 3 with information
elements, Layer 2 and Layer 3 with information elements, Layer 2 and Layer
3 with no information elements, Layer 2 only, or call detail records.
Layer 3 with information elements shows ISDN Layer 3 messages with
information elements on separate lines. Layer 2 only shows ISDN Layer 2
frames and is used for checking Layer 2 handshaking with the near end.
Layer 2 and Layer 3 show identical information for T1 robbed-bit
signaling. Call detail records show basic information such as channel used
and called number. You can set the data capture to execute on all calls,
next incoming call, next outgoing call, or until internal error. As part
of our tests, we captured some test calls and were able to view the data
captured quite easily.
ROOM FOR IMPROVEMENT
Our first suggestion would be to have an optional Windows interface
instead of using a terminal emulator. This would offer obvious advantages.
For instance, although the System 930 allows you to save up to eight
profile configurations, a Windows interface would allow for saving all
your various testing configurations into "project files" on a
Windows PC for easier duplication and re-verification of previous test
results. This would also allow test configurations to be imported into
other System 930 units, as well as allow for easier importing of test
results into other Windows applications, such as Excel or Crystal Reports.
Recorded messages can only be as long as 20 seconds. We feel that 20
seconds might be limiting to some potential customers, and with the price
drops in flash memory and hard disks, longer recordings should be made
available in a future release. Also, a Getting Started Guide with
step-by-step instruction for a common test configuration would be
beneficial to novices.
CONCLUSION
Telephony simulators aren't the most glorious genre of products within
the communications arena, but they perform an essential task. The Gordon
Kapes System 930 Telephony Simulator is an excellent choice for R&D
departments, trade show demonstrations, and much more. TMC Labs was very
pleased with the System 930's simple-to-use interface, bulk call
generation capabilities, superb feature-set, as well as its support for
the T1, E1, and ISDN protocols.
[ Return
To The September 2000 Table Of Contents ] |
Internet Telephony Magazine
Click here to read latest issue
CUSTOMER 
Cloud Computing Magazine
Click here to read latest issue
IoT EVOLUTION MAGAZINE
