- The ASMi-31, Remote Control Sync/Async Short Range
Modem, operates full duplex over twisted pair, 2-wire unconditioned lines.
It has a transmission range of up to 8 km (5 miles) over 24 AWG wire (see
Table 1) and operates at user selectable rates from 1.2 kbps to 128 kbps.
- The modem uses 2B1Q line code and adaptive
equalizers, which provide immunity to background noise, eliminate normal
line distortion and enable efficient transmission over 2-wire twisted pair
- Transmit timing is either provided internally, or
recovered from the received signal (user-selectable). Alternatively, the
transmit timing can be detected automatically and derived externally from
the digital interface, enabling tail-end applications. The carrier may be
continuous or controlled by RTS, for passing control signals end-to-end
- ASMi-31 supports a wide range of digital
interfaces: V.24/RS-232, V.35, X.21, RS-530, V.36/RS-449 and G.703
Codirectional (64 kbps). In addition, an Ethernet/802.3 bridging option
enables direct connections of an Ethernet LAN to both sides of the ASMi-31
- The ASMi-31 system configuration is stored in
non-volatile memory, minimizing system down-time when power is down or
when a faulty remote unit is replaced.
- Setup, status, alarms and diagnostics can be
monitored and activated from the ASMi-31 front panel, or via a standalone
portable control unit (PCU). Alternatively, the ASMi-31 can be managed
from an ASCII terminal or an SNMP Unix/PC station connected to LRS-12/24.
- Line interface circuitry protects against lightning
and power surges.
- ASMi-31 is available as a standalone unit in both
ASMi-31/M "Master" and ASMi-31/S "Slave" versions. The master version has
a front panel LCD and control switches. The slave unit has a blank panel,
which prevents unauthorized changes to link parameters. ASMi-31 is also
available as a card for central solutions.
- 2-wire, full duplex, short range modem
- Remote management using an in-band channel
- 2B1Q line coding
- Operating range up to 8 km (5 miles) over 24 AWG
wire, independent of data rate
- Real-time alarm indication for local and remote
- Selectable data rates from 1.2 kbps up to 128 kbps
- Fully compatible with ASM-31 and SRM-31
- Works opposite MP-2100/HS-U module and U-RPT
- Card version for ASM-MN-214 19" rack and LRS-12 19"
rack with central SNMP management
- Configuration and monitoring of local and remote
units from front panel
- V.54 and built-in BER tester diagnostics
- Supports various digital interfaces: V.24/RS-232,
V.35, X.21, V.36/RS-449, RS-530, G.703 Codirectional, or built-in Ethernet
- Automatic rate detection in external clock mode
Figure 1. Central Site Application
Figure 2. ASMi-31 Working Opposite HS-U
card in Megaplex-2100