Overview
The MX25 is a modular device that is capable of operating in two different modes. In one mode of operation, the MX25 is a stand alone SIP to PSTN gateway. When operating in this mode, the MX25 converts the format of a phone call to allow it to pass between the IP network and the public telephone network. The MX25 is also capable of operating as a system that extends the functions of the MX250 to a branch office with 25 or fewer users. In this configuration, the MX25 communicates with the MX250 and exchanges information regarding users and devices. Even when there is a failure in the WAN link connecting the MX250 and the MX25, the MX25 continues to operate and allows for incoming and outgoing calls to the PSTN.

Key Features

• Mode for standalone SIP gateway
• Mode for remote operation in multi-site deployment of MX250
• Remote survivability functions
• 30 channels of speech traffic to PSTN
• Modular installation of telephony circuits
• 8 to 24 analog FXO circuits
• 8 to 24 analog FXS circuits
• 1 T1 circuit (CAS or ISDN
• 1 E1 circuit (ISDN)
• 4 to 12 ISDN BRI circuits (S/T)
• Flexible dial plan
• Interoperates with any standards based network infrastructure
• Based on highly stable embedded Linux operating system

Telephony
There are three slots in the MX25 which allow for the insertion of plug in modules. These modules provide connections to devices such as phones and fax machines, and connection to the PSTN. For connecting to analog phones and fax machines, an FXS module is used. For connecting to the PSTN using analog, an FXO module is used. For connecting to the PSTN using ISDN BRA, a BRI S/T module is used. Both Japanese ISDN and ETSI ISDN are supported on the BRA interface. An MX25 can accomodate any combination of these cards. For connecting to the PSTN using T1 or E1, a T1/E1 module is provided. Only one of these cards can be inserted into an MX25 and only one T1 or E1 circuit can be used. For T1, the protocol can be CAS or ISDN. The CAS protocols supported include Loop Start, Ground Start, Immediate Start, and E&M Wink Start. The ISDN protocols supported include Lucent Custom, Nortel Custom, US National, and INS1500. For E1, the protocol is ETSI ISDN.

Extender for MX250 (Mode 2)
When the MX25 is configured to work in conjunction with an MX250, relevant user and device information is propagated from the MX250 to the MX25. After the MX25 has the information, it is retained even if there is a loss of communication with the MX250. The MX25 uses this information to make intelligent routing decisions for incoming calls.

Normal Operation
During normal operation, the IP phones located at the branch office register with the MX250 at the main site. The phones consider the MX250 their primary SIP server. The IP phones also register with the MX25 and consider it their backup SIP server. This provides a level of redundancy when communication with the primary SIP server is not possible.

The MX25 sends a registration to the MX250 for each analog phone, fax machine, or credit card reader configured on an analog FXS module. This is how the MX250 knows how to route an incoming call on one of its interfaces to an analog extension on the MX25.

When there is an incoming call from the PSTN on the MX25, the call is redirected over the IP network to the MX250. The MX25 decides where to route the call. When an outgoing call is made using any IP phone, the call setup is performed by the MX250. The dial plan on the MX250 is configured by the administrator to provide least cost routing.

Operation when WAN fails
When The MX25 supports a dial plan that is configured by the administrator to provide intelligent call routing to any of its configured PSTN interface groups. When the WAN link fails and the IP phones can no longer communicate with the MX250, they automatically attempt to make calls through the MX25 (backup SIP server). Because of this, outgoing calls from the IP phones are routed locally to the PSTN through the MX25.

Incoming calls on the PSTN are routed intelligently to the proper devices. The MX25 accomplishes this locally by using the user and device information that it retrieved from the MX250 when connectivity was available. The administrator can also configure the MX25 to route all incoming calls from the PSTN to specific devices.

When the WAN connection is restored, communication with the MX250 resumes and normal operation is automatically restored. No intervention is required from the administrator.

SIP Gateway (Mode 1)
The MX25 can provide the functionality of a modular SIP gateway, which is beneficial for a host of applications for the enterprise. Its dial plan allows for routing among multiple SIP servers (internal or external) as well as telephony circuits, which makes it functional within almost every VoIP application.

• Flexible Dial Plan
• Connecting analog devices to to a SIP network
• Connecting a SIP network to the PSTN
• Connecting a SIP network to both PSTN and analog devices
• Connecting telephony system to a SIP network
• Connecting two telephony systems together using SIP

Data Networking
The MX25 provides a single 10/100Base-T circuit that connects to an external Ethernet switch. The Ethernet port can be configured to support IEEE 802.1q VLANs and IEEE 802.1p quality of service at the Ethernet layer. For quality of service at the IP layer, Differentiated Services is supported.

System Capacities
The analog FXS and FXO are octal modules and the BRA is a quad module, supporting 4 (2B+D) circuits. The T1/E1 module provides two physical circuits, however, only one circuit can be used in an MX25 (both circuits can be used when the module is purchased for an MX250). Any combination of modules can be used, but only a maximum of 30 concurrent voice channels to the PSTN is supported.

The MX25 can learn the information of up to 25 users from an MX250. It can accommodate up to 100 simultaneous SIP registrations.

System Administration
The MX25 is administered using a single graphical user interface that runs under Windows 2000 or Windows XP. This interface provides the administrator with a powerful tool that allows for configuration, maintenance, and troubleshooting. When used in conjunction with an MX250, the configuration information can be automatically sent to the MX25.

Power
The MX25 derives its power from ac. The universal ac input operates from 90 Vac to 240 Vac, 47 Hz to 60 Hz. The maximum power drawn by the MX25 is 19 W.

The MX25 has an analog port that is marked as a System Failure Transfer (SFT) port. This is a special port that directly connects to the first analog FXO circuit when power is lost and there is an analog FXO module in slot 1. This allows for a direct connection to the central office so dial tone can be received and calls can be made.

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: 2.27 kg (5 lb)
Size: 270 mm (W) x 210 mm (D) x 85 mm (H) (11” x 8” x 3”)
Mount: Standard 19" rack from front, mid, or rear; 2 RU (89 mm)
Safety: UL 60950, CSA-C22.2, EN 60950:2001
EMI: FCC Part 15, ICES-003 class A, CISPR 22, AS/NZS 3548 Class A
EMC: CISPR 24 (EN55024:1998), EN61000-4
Warranty: one year

Technology
The MX25 uses custom hardware that incorporates all of the processing power and resources required to scale from 1 to 25 users. It is 100% based on open standards, utilizing a real time Linux operating system and SIP for call control. This ensures interoperability, security, and high quality voice. The modular design allows for flexibility of configuration and provides room for future growth.

Please call us 800-884-6945 for MX25 Options and Upgrades!