All MIBs › RS232-MIB
Category: Serial Interface
Description:
Manages RS-232 serial interface configuration, control signals, and port statistics.
Imported Objects
From RFC-1212
| OBJECT-TYPE |
From RFC1155-SMI
| Counter | |
| experimental |
What Is RS232-MIB?
RS232-MIB is a vendor-neutral IETF standards-based MIB (RFC 1659) for managing RS-232-C and related EIA/TIA serial interfaces on any device that exposes serial ports for out-of-band management. It defines objects for serial port configuration such as baud rate, parity, and flow control, along with modem/DTE-DCE control signal states and per-port input/output statistics. Its monitoring value lies in verifying that a serial console or async port's control signaling and configuration match expectations and in tracking traffic/error counters on that port -- a hardware-interface-status MIB for legacy serial connectivity rather than one covering CPU, memory, or environmental sensors. It is a standalone IETF standards MIB but is commonly used together with the CHARACTER-MIB and IF-MIB conventions on devices that expose serial ports through ifTable. It is typically deployed on routers, terminal servers, and other network equipment offering RS-232 console or auxiliary ports. Engineers implementing or auditing this functionality typically reference the RS232-MIB RFC/standard documentation for the authoritative specification.
IPNetwork Monitor allows you to monitor SNMP objects defined in RS232-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.
What Can Be Monitored
- serial port configuration (baud rate, parity, flow control)
- control signal states (DTR/DCD/RTS/CTS)
- input/output byte and error counts
- port connection status
Supported Devices
- vendor-neutral, standards-based MIB, not tied to a specific manufacturer
- any network device with RS-232 serial/console ports (routers, terminal servers, modems)
Monitoring Examples
No object or table names were captured for this MIB (sample_objects is empty), so a specific polling example cannot be given with confidence. RFC 1659 defines an rs232PortTable/rs232PortEntry-style structure for per-port configuration and control-signal status, which an administrator would poll to confirm DTR/DCD signal state and detect a disconnected serial console session, but this is based on the well-known RFC structure rather than grounded sample data.
OIDs
| OID symbolic | OID numeric | Type | Access | Description |
|---|---|---|---|---|
| rs232 | 1.3.6.1.3.20 | |||
| INT rs232Number | 1.3.6.1.3.20.1 | INTEGER | read-only | The number of ports (regardless of their current state) in the RS-232-like general port table. |
| rs232PortTable | 1.3.6.1.3.20.2 | not-accessible | A list of port entries. The number of entries is given by the value of rs232Number. | |
| rs232PortEntry | 1.3.6.1.3.20.2.1 | not-accessible | Status and parameter values for a port. | |
| INT rs232PortIndex | 1.3.6.1.3.20.2.1.1 | INTEGER | read-only | A unique value for each port. Its value ranges between 1 and the value of rs232Number. By convention and if possible, hardware port numbers map directly to external connectors. The value for each port must remain constant at least from one re-initialization of the network management agent to the next. |
| INT rs232PortType | 1.3.6.1.3.20.2.1.2 | INTEGER | read-only | The port's hardware type. |
| INT rs232PortInSigNumber | 1.3.6.1.3.20.2.1.3 | INTEGER | read-only | The number of input signals for the port in the input signal table (rs232PortInSigTable). The table contains entries only for those signals the software can detect. |
| INT rs232PortOutSigNumber | 1.3.6.1.3.20.2.1.4 | INTEGER | read-only | The number of output signals for the port in the output signal table (rs232PortOutSigTable). The table contains entries only for those signals the software can assert. |
| INT rs232PortInSpeed | 1.3.6.1.3.20.2.1.5 | INTEGER | read-write | The port's input speed in bits per second. |
| INT rs232PortOutSpeed | 1.3.6.1.3.20.2.1.6 | INTEGER | read-write | The port's output speed in bits per second. |
| rs232AsyncPortTable | 1.3.6.1.3.20.3 | not-accessible | A list of asynchronous port entries. The maximum entry number is given by the value of rs232Number. Entries need not exist for synchronous ports. | |
| rs232AsyncPortEntry | 1.3.6.1.3.20.3.1 | not-accessible | Status and parameter values for an asynchronous port. | |
| INT rs232AsyncPortIndex | 1.3.6.1.3.20.3.1.1 | INTEGER | read-only | A unique value for each port. Its value is the same as rs232PortIndex for the port. |
| INT rs232AsyncPortBits | 1.3.6.1.3.20.3.1.2 | INTEGER | read-write | The port's number of bits in a character. |
| INT rs232AsyncPortStopBits | 1.3.6.1.3.20.3.1.3 | INTEGER | read-write | The port's number of stop bits. |
| INT rs232AsyncPortParity | 1.3.6.1.3.20.3.1.4 | INTEGER | read-write | The port's sense of a character parity bit. |
| INT rs232AsyncPortAutobaud | 1.3.6.1.3.20.3.1.5 | INTEGER | read-write | A control for the port's ability to automatically sense input speed. When rs232PortAutoBaud is 'enabled', a port may autobaud to values different from the set values for speed, parity, and character size. As a result a network management system may temporarily observe values different from what was previously set. |
| CTR rs232AsyncPortParityErrs | 1.3.6.1.3.20.3.1.6 | Counter | read-only | Total number of characters with a parity error, input from the port since system re-initialization and while the port state was 'up' or 'test'. |
| CTR rs232AsyncPortFramingErrs | 1.3.6.1.3.20.3.1.7 | Counter | read-only | Total number of characters with a framing error, input from the port since system re-initialization and while the port state was 'up' or 'test'. |
| CTR rs232AsyncPortOverrunErrs | 1.3.6.1.3.20.3.1.8 | Counter | read-only | Total number of characters with an overrun error, input from the port since system re-initialization and while the port state was 'up' or 'test'. |
| rs232SyncPortTable | 1.3.6.1.3.20.4 | not-accessible | A list of synchronous port entries. The maximum entry number is given by the value of rs232Number. Entries need not exist for asynchronous ports. | |
| rs232SyncPortEntry | 1.3.6.1.3.20.4.1 | not-accessible | Status and parameter values for a synchronous port. | |
| INT rs232SyncPortIndex | 1.3.6.1.3.20.4.1.1 | INTEGER | read-only | A unique value for each port. Its value is the same as rs232PortIndex for the port. |
| INT rs232SyncPortClockSource | 1.3.6.1.3.20.4.1.2 | INTEGER | read-write | Source of the port's bit rate clock. 'split' means the tranmit clock is internal and the receive clock is external. |
| CTR rs232SyncPortFrameCheckErrs | 1.3.6.1.3.20.4.1.3 | Counter | read-only | Total number of frames with an invalid frame check sequence, input from the port since system re-initialization and while the port state was 'up' or 'test'. |
| CTR rs232SyncPortTransmitUnderrunErrs | 1.3.6.1.3.20.4.1.4 | Counter | read-only | Total number of frames that failed to be transmitted on the port since system re-initialization and while the port state was 'up' or 'test' because data was not available to the transmitter in time. |
| CTR rs232SyncPortReceiveOverrunErrs | 1.3.6.1.3.20.4.1.5 | Counter | read-only | Total number of frames that failed to be received on the port since system re-initialization and while the port state was 'up' or 'test' because the receiver did not accept the data in time. |
| CTR rs232SyncPortInterruptedFrames | 1.3.6.1.3.20.4.1.6 | Counter | read-only | Total number of frames that failed to be received or transmitted on the port due to loss of modem signals since system re-initialization and while the port state was 'up' or 'test'. |
| CTR rs232SyncPortAbortedFrames | 1.3.6.1.3.20.4.1.7 | Counter | read-only | Number of frames aborted on the port due to receiving an abort sequence since system re-initialization and while the port state was 'up' or 'test'. |
| rs232InSigTable | 1.3.6.1.3.20.5 | not-accessible | A list of port input control signal entries. | |
| rs232InSigEntry | 1.3.6.1.3.20.5.1 | not-accessible | Input control signal status for a hardware port. | |
| INT rs232InSigPortIndex | 1.3.6.1.3.20.5.1.1 | INTEGER | read-only | The value of rs232PortIndex for the port to which this entry belongs. |
| INT rs232InSigName | 1.3.6.1.3.20.5.1.2 | INTEGER | read-only | Identification of a hardware signal, as follows: rts Request to Send cts Clear to Send dsr Data Set Ready dtr Data Terminal Ready ri Ring Indicator dcd Received Line Signal Detector sq Signal Quality Detector srs Data Signaling Rate Selector srts Secondary Request to Send scts Secondary Clear to Send sdcd Secondary Received Line Signal Detector |
| INT rs232InSigState | 1.3.6.1.3.20.5.1.3 | INTEGER | read-only | The current signal state. |
| CTR rs232InSigChanges | 1.3.6.1.3.20.5.1.4 | Counter | read-only | The number of times the signal has changed from 'on' to 'off' or from 'off' to 'on'. |
| rs232OutSigTable | 1.3.6.1.3.20.6 | not-accessible | A list of port output control signal entries. | |
| rs232OutSigEntry | 1.3.6.1.3.20.6.1 | not-accessible | Output control signal status for a hardware port. | |
| INT rs232OutSigPortIndex | 1.3.6.1.3.20.6.1.1 | INTEGER | read-only | The value of rs232PortIndex for the port to which this entry belongs. |
| INT rs232OutSigName | 1.3.6.1.3.20.6.1.2 | INTEGER | read-only | Identification of a hardware signal, as follows: rts Request to Send cts Clear to Send dsr Data Set Ready dtr Data Terminal Ready ri Ring Indicator dcd Received Line Signal Detector sq Signal Quality Detector srs Data Signaling Rate Selector srts Secondary Request to Send scts Secondary Clear to Send sdcd Secondary Received Line Signal Detector |
| INT rs232OutSigState | 1.3.6.1.3.20.6.1.3 | INTEGER | read-only | The current signal state. |
| CTR rs232OutSigChanges | 1.3.6.1.3.20.6.1.4 | Counter | read-only | The number of times the signal has changed from 'on' to 'off' or from 'off' to 'on'. |
RFC description
Standard SNMP MIB (RFC 1659) for managing RS-232 serial ports on network devices. Defines management objects for monitoring and configuring serial port parameters, line characteristics, and port status.
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