Access 4000 X.25-TCP/IP Gateway and Terminal Server

• 2 multi-protocol serial ports configurable for X.25, async/serial, or sync/HDLC/LAPB
• 4 RS232 async/serial ports for TCP terminal server applications
• Sync ports support speeds up to 10Mbps, async to 115.2Kbps
• Up to 1024 SVC and/or PVC logical channel connections per X.25 link
• Encapsulation method configurable on a per connection basis
• X.25 link sharing between X.25 and TCP/IP networks
• No re-configuration of existing X.25 devices necessary
• Easy to use web configuration GUI

Software

• Gateway connectivity between X.25 and TCP/IP devices or networks
• XOT (RFC 1613 - X.25 Over TCP)
• X.25 SVC and PVC – 1024 channels / link
• Comprehensive address matching and routing table
• Serial support for terminal server applications
• Telnet and SSH remote management logins
• Optional serial Console port management login
• SNMP polls and link alarms
• User-friendly web interface for easy configuration and monitoring

Hardware

• 2 - DB25F sync/async ports (RS232/V.24, V.35, X.21, RS530, RS449/V.36)
• 4 - DB9M async/serial ports (RS232/V.24)
• RJ45 10/100-BaseT Ethernet port
• -48VDC powered (external 100/240VAC adapter available)
• Enclosure dimensions (D x W x H): 5.4” x 14” x 1.72”
• 1U 19" rack mounted enclosure
• Weight: 4 lbs
• CE and RoHS

Custom Enhancements

Please contact sales with your custom design requirements.

X.25 to TCP Conversion

The X.25 to TCP Conversion Gateway interfaces or bridges between X.25 and TCP/IP devices by interconnecting X.25 logical channels to TCP sockets using one of several encapsulation methods. The Gateway connects directly to X.25 DTE devices or to X.25 packet networks (DCE).

An important function of gateway conversion is the preservation of application messages. X.25 implementations delineate messages using packet sequences and a “More-bit” to reconstruct long messages. TCP, on the other hand, delivers messages as a non-delimited byte stream, and so requires the addition of an encapsulation header on top of TCP to preserve the boundaries of the message. Supported encapsulation methods include:

• XOT (RFC1613 - X.25 over TCP)
• RFC1006 Encapsulation (ISO Transport Service on TCP)
• Cisco RBP
• Odette FTP Encapsulation on TCP (as per RFC5024)
• 2-byte length header
• X.25 M-bit and Q-bit preservation header
• LINE mode for terminal applications
• RAW (when no encapsulation header is required)
• Other encapsulation methods are available by request

X.25 over TCP Encapsulation (XOT)

An XOT gateway is typically used when the X.25 network or point-to-point connection between X.25 devices is being replaced with an IP network. By tunneling the X.25 packets over TCP, transparency is maintained while providing X.25 to IP address mapping and end-to-end X.25 logical channel number translation. X.25 devices do not need to be re-configured when using XOT to replace an X.25 network.

XOT to TCP Conversion

When an IP host supports X.25 on top of TCP (XOT) and relies on an external X.25 gateway to convert back to X.25, a second X.25-TCP gateway would be required for conversion to a TCP/IP device. The Access 1000 Gateway goes one step further by combining XOT–X.25 de-encapsulation and X.25-TCP conversion internally, eliminating the X.25 physical interface and associated overhead or bottleneck.

Serial to TCP Conversion

The terminal server application interconnects devices with asynchronous serial interfaces to TCP/IP servers or clients. This can replace dialup modems and X.25 PAD service. The terminal server interface supports RS232/V.24 with the following settings:

• Speed: 300 to 115200 bps
• Data bits: 5, 6 ,7, 8
• Parity: even, odd, none
• Stop bits: 1, 2
• Flow control: RTS/CTS, XON/XOFF, none

Synchronous to TCP Conversion

The synchronous server application interconnects devices with synchronous serial interfaces to TCP/IP hosts. This can replace dialup modems and X.25 PAD service. The synchronous server interface supports the following settings:

• Interface: RS232/V.24, V.35, X.21, RS449/V.36, RS530
• Clock source: external or internal
• Speed: 1200 bps to 10 Mbps
• Parity generation and checking: CRC-16, CRC-32, none
• Encoding: NRZ, NRZI