Cables

Gcom® provides a number of different cables to meet your specific connectivity requirements.

Cable Function RS232 EIA530 V.35
PCI Pinouts Pinouts Pinouts
Back-to-back test Pinouts Pinouts Pinouts
DCE emulation Pinouts Pinouts Pinouts
Line monitor test Pinouts Pinouts Pinouts

The RS232 and EIA530 cables are identical - they are wired in such a way that the cables are compatible with both standards. Both standards use a DB25 connector.

RS232/EIA530 PCI Cable Pinouts

Use this RS232 or EIA530 cable to connect a DTE (on left) to a DCE (on right). The pin numbers are shown in the form x/y. The x pin is for both RS232 and EIA530 and is the A side of the EIA530 circuit. The y pin is for EIA530 only and is the B side of the circuit.

RS232/EIA530 PCI cable pinouts

Both RS232 and EIA530 use a DB25 connector. Typically a DTE ends in a DB25M (male connector) and a DCE ends in a DB25F (female connector). Thus, the diagram shows a DB25F on the left where it plugs into a DTE and a DB25M on the right where it plugs into a DCE.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

If you use this cable with a Gcom adapter on the DTE end, the appropriate clocking option value is 0.

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V.35 PCI Cable Pinouts

V.35 cable pinouts

Use this V.35 cable to connect a DTE (on left) to a DCE (on right). The pin letters are shown in the form x/y. The x pin is the A side of the V.35 circuit. The y pin is the B side of the circuit.

V.35 uses a 34-pin connector. Typically a DTE ends in a male connector (34PIN M) and a DCE ends in a female connector (34PIN F). Thus, the diagram shows a 34PIN F on the left where it plugs into a DTE and a 34PIN M on the right where it plugs into a DCE.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

If you use this cable with a Gcom adapter on the DTE end, the appropriate clocking option value is 0.

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RS232/EIA530 Back-to-back Test Cable Pinouts

Use this RS232 or EIA530 symmetrical cable to connect two ports back to back. The pin numbers are shown in the form x/y. The x pin is for both RS232 and EIA530 and is the A side of the EIA530 circuit. The y pin is for EIA530 only and is the B side of the circuit.

RS232/EIA530 back-to-back cable pinouts

Both RS232 and EIA530 use a DB25 connector. Typically a DTE ends in a DB25M (male connector) and a DCE ends in a DB25F (female connector). Thus, the diagram shows a DB25F on both ends where it plugs into a DTE.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

The receive clock of each cable end (pins 17/9) is driven from the DTE transmit clock at the other cable end (pins 24/11). The DTE transmit clock (24/11) is jumpered back to the local transmit clock (15/12). This provides the appearance of external clocking at the connector - so you can attach a data line monitor or use the Gcom_xray utility to observe the message flow in both directions. The transmit and receive data lines are crossed so that the transmit data pin on one end of the cable is connected to the receive data pin on the other end.

The modem control signals RTS, CTS, DTR, DCD, and DSR are fed back on each end of the cable. The RTS/CTS looping allows a connected DTE to operate in either half-duplex or full-duplex mode. In half-duplex mode, the DTE perceives that CTS changes state immediately upon a change in RTS state. The DTR/DSR/DCD looping gives the appearance of modem readiness and connection as soon as the DTE asserts DTR.

If you use this cable with a Gcom adapter on either DTE end, the appropriate clocking option value is 1.

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V.35 Back-to-back Test Cable Pinouts

Use this V.35 symmetrical cable to connect two ports back to back. The pin numbers are shown in the form x/y. The x pin is the A side of the V.35 circuit. The y pin is the B side of the circuit.

V.35 back-to-back test cable pinouts

V.35 uses a 34-pin connector. Typically a DTE ends in a male connector (34PIN M) and a DCE ends in a female connector (34PIN F). Thus, the diagram shows a 34PIN F on both ends where it plugs into a DTE.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

The receive clock of each cable end (pins V/X) is driven from the DTE transmit clock at the other cable end (pins Y/AA). The DTE transmit clock (U/W) is jumpered back to the local transmit clock (Y/AA). This provides the appearance of external clocking at the connector - so you can attach a data line monitor or use the Gcom_xray utility to observe the message flow in both directions. The transmit and receive data lines are crossed so that the transmit data pin on one end of the cable is connected to the receive data pin on the other end.

The modem control signals RTS, CTS, DTR, DCD and DSR are fed back on each end of the cable. The RTS/CTS looping allows a connected DTE to operate in either half-duplex or full-duplex mode. In half-duplex mode, the DTE perceives that CTS changes state immediately upon a change in the RTS state. The DTR/DSR/DCD looping gives the appearance of modem readiness and connection as soon as the DTE asserts DTR.

If you use this cable with a Gcom adapter on either DTE end, the appropriate clocking option value is 1.

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RS232/EIA530 DCE Emulation Cable Pinouts

Use this RS232 and EIA530 asymmetrical cable to emulate a DCE from a port on a Gcom synchronous adapter. The pin numbers are shown in the form x/y. The x pin is for both RS232 and EIA530 and is the A side of the EIA530 circuit. The y pin is for EIA530 only and is the B side of the circuit.

RS232/EIA530 DEC emulation cable pinouts

Both RS232 and EIA530 use a DB25 connector. Typically a DTE ends in a DB25M (male connector) and a DCE ends in a DB25F (female connector). Thus, the diagram shows a DB25F on both ends where it plugs into a DTE.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

The left end of the cable connects to a Gcom synchronous adapter. The right end connects to a DTE. The Gcom adapter provides clocking on pins 24/11, which are routed to the TxC and RxC on the DCE (right) end of the cable. This clock routing makes the cable asymmetrical. The cable does not function correctly unless the left connector is connected to a port on a Gcom adapter.

The modem control signals RTS, CTS, DTR, DCD, and DSR are fed back on each end of the cable. The RTS/CTS looping allows a connected DTE to operate in either half-duplex or full-duplex mode. In half-duplex mode, the DTE perceives that CTS changes state immediately upon a change in RTS state. The DTR/DSR/DCD looping gives the appearance of modem readiness and connection as soon as the DTE asserts DTR.

If you use this cable with a Gcom adapter, the appropriate clocking option value is 2.

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V.35 DCE Emulation Cable Pinouts

Use this V.25 asymmetrical cable to emulate a DCE from a port on a Gcom synchronous adapter. The pin letters are shown in the form x/y. The x pin is the A side of the V.35 circuit. The y pin is the B side of the circuit. 

V.35 DCE emulation cable pinouts

V.35 uses a 34-pin connector. Typically a DTE ends in a male connector (34PIN M) and a DCE ends in a female connector (34PIN F).  Thus, the diagram shows a 34PIN F on both ends where it plugs into a DTE.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

The left end of the cable connects to a Gcom synchronous adapter. The right end connects to a DTE. The Gcom adapter provides clocking on pins U/W, which is routed to the TxC and RxC on the DCE (right) end of the cable. This clock routing makes the cable asymmetrical. The cable does not function correctly unless the left connector is connected to a port on a Gcom adapter.

The modem control signals RTS, CTS, DTR, DCD and DSR are fed back on each end of the cable. The RTS/CTS looping allows a connected DTE to operate in either half-duplex or full-duplex mode. In half-duplex mode, the DTE perceives that CTS changes state immediately upon a change in the RTS state. The DTR/DSR/DCD looping gives the appearance of modem readiness and connection as soon as the DTE asserts DTR.

If you use this cable with a Gcom adapter adapter, the appropriate clocking option value is 2.

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RS232/EIA530 Line Monitor Test Cable Pinouts

Turn your Gcom synchronous serial adapter into a real-time data line monitor using the line monitor test cable and Gcom's Xray software.

Use this RS232 or EIA530 cable to monitor serial synchronous traffic. The pin numbers are shown in the form x/y. The x pin is for both RS232 and EIA530 and is the A side of the EIA530 circuit. The y pin is for EIA530 only and is the B side of the circuit.

RS232/EIA530 line monitor test cable pinouts

Both RS232 and EIA530 use a DB25 connector. Typically a DTE ends in a DB25M (male connector) and a DCE ends in a DB25F (female connector). Thus, the top portion of the diagram shows a DB25F on the end that connects to a DTE and a DB25M on the end that connects to a DCE. The bottom portion of the diagram shows two DB25F connectors that connect to two ports on a Gcom synchronous adapter.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

The top portion of the cable is a straight-through cable. You can insert this cable at the desired point of observation on any RS232 or EIA530 circuit.

The bottom portion of the cable connects to two ports on a Gcom synchronous adapter. The bottom left connector monitors traffic on the transmit data line. The bottom right connector monitors traffic on the receive data line. There must be clocks present on the TxC and RxC circuits of the monitored line. Thus, for example, this cable cannot be used to monitor both directions of traffic on a connection that uses the Gcom back-to-back cable because the TxC pin is not wired in those cables.

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V.35 Line Monitor Test Cable

Turn your Gcom synchronous serial adapter into a real-time data line monitor using the line monitor test cable and Gcom's Xray software.

Use this V.35 cable to monitor serial synchronous traffic. The pin numbers are shown in the form x/y. The x pin is the A side of the EIA530 circuit. The y pin is the B side of the circuit.

V.35 line monitor test cable pinouts

V.35 uses a 34-pin connector. Typically a DTE ends in a male connector (34PIN M) and a DCE ends in a female connector (34PIN F).   Thus, the top portion of the diagram shows a 34PIN F on the end that connects to a DTE and a 34PIN M on the end that connects to a DCE. The bottom portion of the diagram shows two 34PIN F connectors that connect to two ports of a Gcom synchronous card.

The arrows indicate the signal flow direction, from DTE to DCE or vice versa. When constructing special cables, make sure the signals flow in the proper directions.

The top portion of the cable is a straight-through cable. You can insert this cable at the desired point of observation on any V.35 circuit.

The bottom portion of the cable connects to two ports on a Gcom synchronous adapter. The bottom left connector monitors traffic on the transmit data line. The bottom right connector monitors traffic on the receive data line. There must be clocks present on the TxC and RxC circuits of the monitor line. Thus, for example, this cable cannot be used to monitor both directions of traffic on a connection that uses the Gcom back-to-back cable because the TxC pin is not wired in those cables.