25-Pin D Connector
Different types of Apple computer or Macintosh computer printer RS-232 pin-outs are
listed below, all using a DB 25 pin connector.
Note that the Apple computer it-self no longer carries an RS232 connector.
A description is provided along with the connector pin outs.
How ever, no electrical standards or cabling information is provided.
Refer to this page for a pin out of Apple RS232 signal assignments over a DB 9-pin connector; Apple RS232 over DB-9 Connector.
Here is a link to DB Connector manufacturers, or
Cable manufacturers, and a list of
Cable Assemblies manufacturers.
A description of the RS-232 [EIA/TIA232] bus is provided on the RS232 bus page.
The Serial port, or RS232 port no longer appears on Apple computers. The RS232 interface is
obsolete and should not be used in new designs.
The Apple Computer Serial Pinout and Signal names on a 25-Pin D-Sub connector (RS-232)
Used on LaserWriter Select 360
| Pin Number |
Signal name |
Signal Description |
|---|---|---|
| 1 | GND | Ground |
| 2 | /TXD | Transmit Data |
| 3 | /RXD | Receive Data |
| 4 | RTS | Request To Send |
| 7 | GND | Ground |
| 8 - 19 | NC | Not Connected |
| 20 | DTR | Data Terminal Ready |
| 21 - 25 | NC | Not Connected |
The ImageWriter is a dot-matrix printer. A Laser printer is called a LaserWriter.
Note that dot-matrix printers are out-dated, having been replaced by laser printers years ago.
The Apple Computer Serial Pinout and Signal names on a 25-Pin D-Sub connector (RS-232)
Used on LaserWriter Personal NTR printer.
Note, not all peripherals require all the lines associated with the RS232 interface.
The un-used lines are shown as N/C or no-connect, or maybe not-connected.
| Pin | name | Description |
|---|---|---|
| 1 | GND | Ground |
| 2 | TXD | Transmit Data |
| 3 | RXD | Receive Data |
| 4 | RTS | Request To Send |
| 5 | CTS | Clear To Send |
| 6 | DSR | Data Set Ready |
| 7 | GND | Ground |
| 8 | DCD | Data Carrier Detect |
| 20 | DTR | Data Terminal Ready |
| 9 - 19 | NC | Not Connected |
| 20 | DTR | Data Terminal Ready |
| 21 | NC | Not Connected |
| 22 | RI | Ring Indicator |
| 23 - 25 | NC | Not Connected |
The table below shows the RS232 pin out as found on an Apple Line Printer
As a general rule, all RS232 connections are the same, but with a pin or two missing.
The only reason to show RS232 connections for different devices is to detail the missing pins
Otherwise the pinout should conform to the RS232 standard.
A description of the RS-232
[EIA/TIA232] bus is provided on the RS232 bus page.
Which also describes the connector signals and their functions over the interface.
| Pin | name | Description |
|---|---|---|
| 1 | SNG | Shield ground |
| 2 | TXD | Tx Transmit Data, Out |
| 3 | RCD | Rx Receive Data, In |
| 4 | RTS | Request to Send, Out |
| 5 | CTS | Clear to Send, In |
| 6 | DSR | Data Set Ready, In |
| 7 | GND | Ground |
| 8 | DCD | Data Carrier Detect, In |
| 9 | n/c | No connection |
| 10 | ||
| 11 | ||
| 12 | CH | Data signal rate selector, In |
| 13 | n/c | No connection |
| 14 | ||
| 15 | ||
| 16 | ||
| 17 | ||
| 18 | ||
| 19 | ||
| 20 | DTR | Terminal Ready Signal, Out |
| 21 | n/c | No connection |
| 22 | CE | Ring indicator, In |
| 23 | n/c | No connection |
| 24 | ||
| 25 |
The Apple Computer Serial Pinout and Signal names on a 9-Pin D connector (RS-232).
Used on LaserWriter Pro 600/630
Used on LaserWriter Select 310 (Pins 7 and 8 are unused and not
connected)
| Pin # | Pin name | Pin Description |
|---|---|---|
| 1 | DCD | Data Carrier Detect |
| 2 | /RXD | Receive Data (Inverted) |
| 3 | /TXD | Transmit Data (Inverted) |
| 4 | DTR | Data Terminal Ready |
| 5 | GND | Ground |
| 6 | DSR | Data Set Ready |
| 7 | RTS | Request to Send |
| 8 | CTS | Clear to Send |
| 9 | RING | Ring Signal |
The RS-232 interface is out-dated and obsolete, most computers no longer ship with an RS232 interface.
Other devices use USB or Ethernet. Use either of those interfaces as an upgrade path.
The printers listed here are certainly out-dated but may still be in service, using the pin out as provided in the table.
Many companies will not replace a piece of equipment until it goes back or can no longer be serviced.
The 9 pin connector is more common on peripherals than the 25 pin connector.
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