4-Port RS-232 Modem Sharing Device. Expand leased line, polled environments without adding computer ports or communications links.
- Enables multiple sync/async terminal or DTE devices operating in a polled environment to share one modem.
- Increases network efficiency.
- Transparent to data.
- Fully cascadable.
- Individual subchannel enable/disable switches.
- ±15 kV ESD protection.
The Modem Sharing Device (MSD) provides the network manager with a cost-effective way of expanding existing, leased-line, polled networks without adding computer ports or communications links. Up to four terminals can share the same port and communications link using the contention and control protocols normally resident in the host hardware and software. Once installed, system and network efficiency are increased through higher host processor utilization coupled with the significant decrease in idle time between host/terminal traffic sessions.
Ideal for either synchronous or asynchronous network environments, the MSDs are protocol transparent at data rates up to 128 Kbps. Data arriving at the master port is continually broadcast to all subchannels. The attached terminal device that raises the RTS control signal is automatically given control of the MSD until data transmission is complete. Clocking is accomplished from the attached modem.
The MSDs incorporate optional anti-streaming circuitry. If enabled, anti-streaming will automatically remove a defective terminal from service if the data/control criteria is present for the user-predefined selection period.
Housed in a sturdy metal enclosure and equipped with an internal 110/220-VAC switch-selectable linear power supply, the MSDs will provide in excess of 100,000 hours of reliable service.