Zed-3 | GS8 | Zed-3 GS8 GSM Gateway Datasheet

Zed-3 GS8 GSM Gateway Datasheet
Modular gateway
Connects directly to IP or analog PBX to simplify wiring
Connects to traditional phone systems with analog circuits
Compatible with open standards SIP networks
Connect to wireless and land line phone networks
Free calls to phone network (depending on plan)
Easy expansion of phone lines
Extend PBX extension seamlessly to your mobile phone
Setup an office without needing land lines
Mobile phones become extensions of business PBX
Useful for businesses from SOHO to branch office to
Key Features
Modular gateway supporting analog, CDMA, and GSM
2G, 2.5G, and 3G compatible
Permits mixture of interfaces
Connects to VoIP PBXs and SIP networks with Ethernet
Operates as a gateway (with clustering) without IP PBX
Connects to PBXs, key telephone systems, analog phones, or
analog phone lines
Up to four GSM or CDMA interfaces
Use a single external antenna with RF splitter
Up to eight analog FXO interfaces
Up to four analog FXS interfaces
Up to eight channels of voice
Send and receive voice calls between any interfaces
Passes caller ID for incoming calls
Send and receive SMS and MMS
Captures log of calls and statistics
Simple configuration with web browser
Multiple languages and worldwide support
The Zed-3 GS8 modular gateway is a stand alone gateway
for VoIP, PSTN, and mobile phone networks. It converts
the format of a phone call to allow it to pass among these
networks. The device connects to the PSTN using analog, the mobile network using GSM or CDMA, and the IP
network using SIP.
With this device you obtain great flexibility in how calls
should be routed and have a means to provide telephony
backup in the event the standard telephony path fails
Further, you can significantly reduce the money you
spend on telephony, especially for the cost of calls from
your internal phone system to CDMA or GSM phones.
The GS8 modular gateway is compatible with most IP
PBXs using the SIP protocol, is compatible with traditional (legacy) phone systems with analog circuits, and
can be used separately or in a cluster without any PBX. It
provides a means to easily integrate mobile telephony as
part of your company’s phone system.
Hardware and Telephony
The GS8 modular gateway can be mounted in a 19” rack
and has four slots into which you can plug any interface
module. The GSM, CDMA, and FXS modules have one port
(or circuit) each; the FXO module has two ports (circuits).
The FXS port can connect to analog telephones or to a
PBX (in which case, it appears as the telephone exchange).
The FXO port connects as a subscriber to your PBX or to
the telephone exchange.
When enabled, it provides authentication and two stage
dialling. A call is answered by the GS8 modular gateway
which then prompts the caller to enter a password, a
number, or both, depending on your criteria. When calls
are received on the specific interface, the GS8 modular
gateway will verify the password (if programmed), and
collect the destination phone number. The call is then
routed according to the routing table in the same way it
would be if the IVR was not enabled on that port.
System Administration
If you have a single wireless module, you may be able to
connect a small antenna directly to the module. However,
for better reception, you may want to use an external antenna, connected with coaxial cable to the module. If you
have multiple modules, you should use the antenna splitter (combiner) and then use a single external antenna.
The GS8 modular gateway has an HTML based administration UI so that it is not necessary to install any management software on a PC. The administration UI is intuitive
and easy to navigate. You can access and manage the GS8
modular gateway from anywhere as long as you have a
web browser and access to the Internet.
SIP Operation
The administration UI provides various real time information and statistics of the GS8 modular gateway. These
include operation state, system and network information,
events and alarms, line status, and comprehensive call
detail records (CDRs).
There are two working modes in which the GS8 modular
gateway connects with other SIP devices, including interconnection with other GS8 modular gateways.
The basic working mode is similar to that of a SIP phone
in which the GS8 modular gateway registers to another
SIP device, such as a soft switch or IP PBX.
The second working mode is to connect to other SIP devices without registration. This permits the GS8 modular
gateway to operate independently of an IP PBX and also
permits the clustering of GS8 modular gateways to transparently create a virtual gateway that has more than four
wireless ports.
The GSM and CDMA modules can send and receive SMS
text messages and MMS multimedia messages to or from
a mobile phone. These are transmitted over the Ethernet
port as SIP MESSAGE messages to ensure compatibility
with a variety of different SIP PBXs. You determine for
each module the destination of received SMS or MMS
messages and you can program that SMS and MMS messages are always sent to a person who sent an SMS or
MMS to that phone number within a specified time.
The GS8 modular gateway can send and receive text
messages in 7 bit mode (160 characters per message) or
in Unicode (70 characters per message). It can send and
receive multimedia messages comprising images and
rich text that are limited to 30 KB. The sending or receiving client is responsible for formatting or interpreting the
message to OMA specifications.
IVR (Interactive Voice Response)
The GS8 modular gateway has an IVR function that can
prompt callers. This can be enabled or disabled separately
for the IP, FXO, GSM, and CDMA ports.
Data Networking
Most IP networks existing today support VLAN and QoS
and using these features can increase the voice quality of
phone calls. The GS8 modular gateway fully supports IEEE
802.1Q VLAN tagging and IEEE 802.1p QoS. At the IP layer,
the GS8 modular gateway supports the ability to mark
the lower six bits of the IP QoS byte with the various differentiated service code point (DSCP) markings.
Diagnostics and SNMP
The system chassis has two LEDs on the front to indicate
the status and two LEDs on the Ethernet port. The wireless modules have two LEDs to indicate status and the
analog modules have a single LED per port to indicate
when a call is in progress.
The system provides ping, traceroute, and DNS lookup
for network diagnostics. These tools will help you identify
most networking problems. To identify call setup problems, the system also provides a SIP Route Trace diagnostic tool.
The GS8 modular gateway supports Trap in SNMP. This
allows you to be notified immediately if the system is
experiencing any problems.
Global Features
Zed-3 sells and supports its products worldwide. The GS8
modular gateway supports telephony protocols for many
countries so it can connect directly to the local PSTN. Different modules are available for the GSM frequencies of
850 MHz and 1900 MHz (USA and most of the Americas)
or 900 MHz and 1800 MHz (most of the rest of the world).
The CDMA module operates at 800 MHz, serving most
parts of the world. You can navigate the GS8 modular
gateway’s administration UI in English or Simplified
Application: Basic Use
Equipped with GSM and CDMA modules, the GS8
can connect your office phone system directly to the
mobile phone network. Depending on the calling plan
you have with your carrier, this could mean that calls
to the PSTN or other mobile phones cost nothing for
each call.
The business can also choose to publish the mobile
phone number associated with the ports on the GS8
modular gateway. Callers using a mobile phone may be
able to call the company’s “mobile” number cheaper than
if they called the company’s land line phone number.
This will lead to increased business and customer satisfaction.
Branch Office
Main Office
Application: Use for Backup Communications
If you are using an IP PBX as the communications, and
that PBX is connected directly to an ITSP (internet telephony service provider), you can use the GS8 modular
gateway to provide backup telephony in the event the
internet service fails.
Normal Phone Service
Application: One Number for Executives
As an extension of the previous application, you can
use call forwarding on the PBX to automatically
route inbound calls to your mobile phone.
Depending on the PBX, you may be able to
do this selectively, based on the time of day,
day of week, or caller.
The configuration shown in the figure on the back
page permits the office to make and receive calls over
the mobile network instead of over the PSTN land line.
Some carriers offer free calls among a group of users. By
putting one of the SIM cards in the GS8, calls between
your remote users and the office will be free. Similarly,
some mobile phone carriers have very low cost rates for
international calls compared to an equivalent call on a
land line. By routing all international traffic over the GSM
or CDMA network, your company may have significant
Then when the executive is not in the
office he or she can still receive calls directed to the office
phone. This is achieved without having to disclose the
executive’s mobile phone number to the caller. The call
is forwarded to the mobile phone automatically, with
minimal delay, and at no additional cost to the caller or
the business (depending on the calling plan).
Application: Extension to Other Offices
If you have branch offices, you can extend the calling
from those offices to be transmitted over one GS8 modular gateway, so you don’t need to have multiple gateways
in each office.
The configuration shown in figure 1 permits the remote
office to use the gateway at the main office thereby reducing communications costs in that office, too.
IP Phones
The configuration shown in figure 2 shows an office
making and receiving its normal telephony with the ITSP.
If that service fails, calls can be routed through the GS8
modular gateway to the PSTN or mobile networks.
Alternatively, calls may be routed to the GS8 modular
gateway using a least cost routing (LCR) algorithm in your
PBX. This LCR determines whether a call should be routed
over the ITSP, the analog PSTN network, or over the GSM
or CDMA network. The LCR is programmed to compare
part or all of a dialled number against a list in a routing
table and can, for example, cause calls to a mobile phone
to be made from CDMA or GSM to mobile instead of land
line to mobile.
Application: Connection to Traditional PBX
The GS8 modular gateway can connect to a traditional
PBX to provide flexibility and low cost telephony calls. It
can connect with the FXS or FXO modules.
either permit calls from only a specified mobile phone
or prompt the caller for a password. A public call would
be treated just like a call from the PSTN and always be
routed to the operator or automated attendant.
In the configuration shown in figure 4, the GS8 modular
gateway is connected to standard analog ports on the
PBX with an FXS module. The GSM or CDMA module or
modules are mapped to these analog circuits. The GS8
modular gateway appears like the PSTN (or central office)
to the PBX. Outgoing and incoming calls to the mobile
phone network can be treated identically to those to or
from the PSTN.
Traditional PBX
You can use LCR on the PBX to determine if a call from
the PBX should be routed to the GSM or CDMA network,
or to the PSTN network. Again, call forwarding configured
on the PBX can permit calls to a user to be automatically
routed to a mobile phone.
Application: Reduction of Multiple Mobile
In the configuration shown in figure 3, the GS8 modular
gateway is connected to standard analog ports on the
PBX with an FXO module. The GSM or CDMA module or
modules are mapped to these analog circuits. The GS8
modular gateway appears to the PBX as subscriber extensions. A call to the analog extension on the PBX will be
routed automatically to a mobile phone. This seamlessly
provides a mobile phone user with a wireless extension
on the PBX.
You can choose whether incoming calls are private or
public. A private call would be treated just like any extension call. The system can authenticate the caller and
In many parts of the world, there is fierce competition
among the authorized mobile phone operators. They may
charge little or nothing for calls to other phone numbers
in their network and charge much for calls to phones on a
competing network. This may force an executive to carry
multiple mobile phones and publish multiple mobile
phone numbers on his or her business card. Using the
GS8 modular gateway as shown in figure 5 the executive
now needs to carry only a single mobile phone.
The figure shows a GS8 modular gateway with four GSM
or CDMA modules. The modules are registered with
service providers ‘A’ to ‘D.’ The executive used to carry four
mobile phones and now carries a single mobile phone, in
this case the one registered with provider ‘A.’
Provider Provider Provider
Phone with
provider A
Traditional PBX
Phones (analog or digital)
IP Phones
When a call is received on provider B’s network, the PBX
routes it to the executive’s extension. The executive has a
simple call forwarding rule to redirect all calls to the mobile phone (on provider A’s network). This will probably be
at zero cost and is transparent to the caller.
The GS8 modular gateway can operate in this mode
completely stand alone, without any IP connection. It can
be programmed to route any call received on any one of
its ports to any other port. As the next example shows, it
can operate this way in a cluster so this application can be
extended to five or more mobile phone service providers. The scheme shown in figure 5 has the advantage that
when the executive is in the office he or she can stop the
call forwarding and receive all calls on his or her desk
Application: Clustering of GS8 Modular Gateways without an IP PBX
Figure 6 shows how multiple GS8 modular gateways can
be connected together to create a virtual GS8 modular
gateway with increased capacity. A SIP call can be routed
from one GS8 modular gateway to another GS8 modular gateway. The receiving GS8 modular gateway simply
accepts the call and routes it based on the programmed
routing strategy.
Traditional PBX
modular gateway either directly or through the IP PBX.
On a changing customer situation in the data base, the
middleware can cause an SMS to be sent to the customer.
It can receive a response from the customer and cause
another action in the data base. This will all happen without anyone needing to initiate the transaction or gather
any response.
One example might be a car repair garage. After a
customer’s car has been repaired or serviced, the data
base is updated with the details of the service. The system
can send an SMS to the customer to inform him or her
that the car is ready and the total bill.
Another example might be a dental or optician office that
schedules regular appointments with clients every six
months or so. Usually, the practitioner will call the client
prior to the appointment to ensure he or she has not
forgotten and will confirm the appointment. Instead, the
middleware is programmed to send a reminder by SMS
a few days in advance and request that the client acknowledge attendance by replying “yes” or “no.” A further
reminder can be sent 12 hours before the appointment if
A third application is where a restaurant accepts reservations for booking a table. When the reservation is
accepted the caller’s mobile number is entered into the
data base. The system sends an SMS to the caller with
the address of the restaurant and a confirmation of the
booking date and time. If the booking was made long
in advance, the system can request confirmation of the
appointment with an additional text message a few hours
before the meal.
Each of these examplesModule
is less intrusive
to the client,
requires no intervention in the business, and improves
customer satisfaction.
Multiple GS8
In this example an incoming call from the traditional PBX
can go out to the GSM or CDMA network from any free
GSM or CDMA port, and this GSM or CDMA module does
not have to be in the same chassis as the analog module.
It is theoretically possible to extend this cluster of GS8
modular gateways without the limitation of location and
number of nodes.
Application: Service Business using SMS
This shows how a business can improve customer satisfaction by sending (and receiving) SMS text messages
to customers. Figure 7 shows a company that has a data
base with details about the service provided to the customer and a small piece of middleware software that interfaces to the data base and communicates with the GS8
Data base
running on
IP Phone
Modular gateway
Basic Application
GSM or
Land Line
IP Phones
4 GSM ports (850 & 1900 MHz or 900 & 1800 MHz)
4 CDMA ports (800 MHz)
4 FXS ports (loop start)
8 FXO ports (loop start)
Any mixture of interfaces is permitted
8 channels active simultaneously
Telephony and Messaging
A-law and µ-law G.711, G.729A, G.723.1, GSM
Automatic negotiation of codec
Route audio between any interface
Echo cancellation
Fax support for Group III up to 9.6 kb/s with T.38
Call progress tones for multiple regions
Caller ID screening
Call routing for received and transmitted calls without
external PBX
ASCII and Unicode characters for SMS messages
30 KB MMS (rich text and video)
VoIP and IP Networks
SIP user agent and B2BUA (RFC3261 compliant endpoint)
Operates with and without SIP registration
Simultaneous registration to multiple proxies
Dynamic jitter buffering
Packet loss compensation
Adaptive VAD with CNG
IP TOS, 802.1p/Q VLAN tagging, and DiffServ
DTMF signalling in band, RFC2833, or with SIP Info
Configuration and Management
HTTP interface (uses web browser)
English and Chinese languages for administration
Online upgrade with HTTP
Configuration backup and restore
Least cost routing
RADIUS client
Diagnostic tools: ping, tracer, DNS lookup, SIP
route trace
Comprehensive alarm and event records
Access control list (ACL)
SNMP trap
Hardware Specifications
LED indicators on chassis and modules
SMA connector on GSM and CDMA modules
RJ11 connector(s) on analog modules
Each GSM and CDMA module accommodates one
SIM card
Reset button
One 10/100 Mb/s LAN port
External ac to dc power adapter
Input: 100~240 Vac @ 47~63 Hz
Power: 20 W
Physical and Environmental
Operating temperature: 10°C to 40°C (50°F to 104°F)
Storage temperature: 0°C to 50°C (32°F to 122°F)
Weight: 2.6 kg (5.7 lb). Shipping weight 3.9 kg (8.6 lb)
Size: 440 mm (W) x 225 mm (D) x 45 mm (H) (17.3” x 8.9” x 1.8”)
Safety: FCC Part 68
EMI: FCC Part 15A
RoHS: Compliant
Tel: +1-408-587-9333
501 Valley Way
Fax: +1-408-586-9038
Milpitas, CA 95035
E-mail: zed-3@zed-3.com
Web: www.zed-3.com
Zed-3, the Zed-3 logo, the Zed-3 mark, and GS8 are trademarks of Zed-3. All other trademarks used herein are the property of their respective owners.
Copyright © 2008 Zed-3; all rights are reserved. Specifications are subject to change at any time without notice. Document number 96-00520-02, May 2008.
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