Convenience
The DI-1137’s versatile modular design means it can be configured with various WAN interfaces to suit specific requirements.  Should it become necessary it can be upgraded, for instance, from ISDN to Leased Line, if the on-line time makes continued ISDN use uneconomic.  ISDN charges, are however, controlled by features built into the DI-1137 such as Bonding, Spoofing and link activation timing.

Security
In the Wide Area Network, security is of utmost importance. The DI-1137 meets your strictest requirements to protect against unauthorised entry by providing in-built firewall protection with D-Link NetProtect Firewall.  This allows only specified IP addresses in, blocking all others.  Whilst using NAT and DHCP features provides natural firewall protection.

The filters built into the DI-1137 allow additional tightly controlled access to your sensitive data while allowing free access to authorised users. Two levels of dial-up security are also provided through the XID and password authentication protocols.

ISDN Call Line ID (CLID) provides security by specifying the CLID of those devices from which calls will be accepted and provides CLID screening on call resumption whilst ISDN Callback (also based on CLID) provides a further level of security. Other standard security features include password protection and PAP and CHAP authentication protocols.

Connectivity
DI-1137s can be linked together in a point-to-point topology using one or two high-speed links up to 2.048Mbps (E1) each.  It supports PPP-MP over Leased Line, ISDN and Frame Relay (RFC 1490) over leased Line, supporting up to 128 DLCIs.

One ISDN channel may be used to backup a leased line connection or it can be used to simultaneously access the Internet whist the DI-1137 is connected via a Leased Line to another LAN.

DI-1137s can also be used to link multiple remote LANs together in a multi-point topology, each of its two WAN ports connecting to separate remote routers.  Its unique closed WAN loop feature allows all sites to be inter-connected, for optimal traffic flow, without the need for a redundant link.

When the DI-1137 is used in an ISDN environment it will sense when your data transfer has ceased and will terminate the call, saving call charges, while “spoofing” the services offered by the server(s).  When data is to be transferred again the access to the network service will automatically and transparently be re-established by the DI-1137. 

To ensure complete flexibility, the DI-1137 is available with a selection of LAN and WAN interfaces, 10Base-T, 10Base-2, 10Base-5, ISDN BRI S/T and U, V.11/X.21, V.35,
RS-232/V.24, RS-530/RS-422 and G.703 offering a uniquely superior and flexible solution.