CHAR-MIB

MIB Reference — IPNetwork Monitor · Updated September 14, 2026

All MIBsCHAR-MIB

Category: Network Interfaces

Description: Implements RFC 1658 character stream device management for terminal servers and character-oriented network port hardware.

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What Is CHAR-MIB?

CHAR-MIB is the standard IETF MIB module defined in RFC 1658 for managing character-stream (asynchronous serial/terminal) devices such as terminal servers and character-oriented network ports. It exposes objects describing character port configuration (line speed, parity, flow control) and per-port operational/error statistics for serial character streams. It is a general device/interface management MIB rather than a hardware-health MIB in the CPU/temperature sense, but it does support monitoring port-level operational status and error counters (e.g., framing/parity/overrun errors) that reveal a failing serial line or misconfigured terminal connection. Because it manages character-oriented ports, it is commonly used alongside RFC 1213 (MIB-II) ifTable entries, since each character port typically corresponds to an interface. It is deployed on terminal servers, console/serial concentrators, and other network devices that expose async serial ports for character-based access. Engineers implementing or auditing this functionality typically reference the CHAR-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in CHAR-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

  • vendor-neutral, standards-based MIB, not tied to a specific manufacturer
  • terminal server / character-oriented serial port device

Monitoring Examples

No object or table names were extracted for this MIB (sample_objects is empty), so specific table/object identifiers cannot be cited; based on the RFC 1658 specification, an administrator would typically poll the character device's port configuration objects to confirm line speed/parity/flow-control settings and check per-port error counters (e.g., overrun, framing errors) to identify a failing or misconfigured serial connection.

What Can Be Monitored

  • character port line configuration (speed, parity, flow control)
  • port operational status
  • serial port error counters (framing/parity/overrun)
Imported Objects

From RFC-1212

OBJECT-TYPE

From RFC1155-SMI

Counter
Gauge
TimeTicks
experimental

From RFC1213-MIB

DisplayString
OIDs

RFC description

Character stream device management MIB for port configuration and status monitoring.

Start monitoring Terminal servers / character-oriented serial port devices with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download CHAR-MIB