7E Communications


ISDN S-Bus adaptor for Inmarsat & VSAT

S0DA ISDN adaptorThe 7E Communications S0DA provides a unique interface between the dial-up ISDN S-interface and the serial ports commonly found on VSAT terminals and all Inmarsat-A & B terminals.

Many attractive low-cost ISDN products such as PC based video conferencing systems, routers, Group IV fax and PCMCIA cards are only supplied with an ISDN S-Bus interface. However most satellite communications equipment requires a serial interface, resulting in restricted choice and increased costs for the user. The 7E S0DA solves this problem by providing both a local S-Bus and two serial interfaces (one for each B channel).

The RJ45 from the ISDN device is simply plugged into the adaptor which simulates the ISDN protocol for both outgoing and incoming calls and then presents the 64kbps data stream at the serial interface(s).

The adaptor provides a number of methods for call setup and control, a DTMF interface provide a full dialing capability with suitable Inmarsat-B equipment such as that from CMI and Nera via a spare telephone port. An even simpler solution uses hardware handshaking; on receipt of a call request the adaptor raises DTR and signals the ringing signal to the calling device, then when DCD is returned the call is signalled as answered, a similar procedure is followed for incoming calls. The adaptor is compatible with the Inmarsat-B system and only requires a single adaptor located with the mobile terminal, or pair of terminals if 128kbps capability is required.