Macintosh SE and SE 30: External Pinouts (5/93)
Article Created: 29 April 1993
This article gives the pin assignments and functions for the connectors on the
back panels of the Macintosh SE and SE/30. The pinouts are the same with the
exception of the audio output ports. The Macintosh SE provides a monaural
signal and the Macintosh SE/30 a stereo signal. Appropriate information
appears below.
This article gives the pin assignments and functions for the connectors on the
back panels of the Macintosh SE and SE/30. The pinouts are the same with the
exception of the audio output ports. The Macintosh SE provides a monaural
signal and the Macintosh SE/30 a stereo signal. Appropriate information
appears below.
Apple Desktop Bus (ADB)
-----------------------
Pin Signal name Signal description
1 ADB Data
2 NC Reserved
3 +5v +5 volts DC
4 GND Signal ground
- Connector type: 4-pin minicircular
- Total length of all cables not to exceed 16 feet (5 meters)
SCSI Port (25-pin)
------------------
Pin Signal name Signal description
1 REQ/ Request
2 MSG/ Message
3 I/O/ Input/Output
4 RST/ SCSI bus reset
5 ACK/ Acknowledge
6 BSY/ Busy
7 GND Signal ground
8 DB0/ Data bit 0
9 GND Signal ground
10 DB3/ Data bit 3
11 DB5/ Data bit 5
12 DB6/ Data bit 6
13 DB7/ Data bit 7
14 GND Signal ground
15 C/D/ Common/Data
16 GND Signal ground
17 ATN/ Attention
18 GND Signal ground
19 SEL/ Select
20 DBP/ Data parity
21 DB1/ Data bit 1
22 DB2/ Data bit 2
23 DB4/ Data bit 4
24 GND Signal ground
25 TPWR Terminator power
- Connector type: DB-25
- Total length of all cables not to exceed 20 feet (6 meters)
WARNING: The SCSI port uses the same type of connector as a standard RS-232,
DB-25 serial interface, but it is different electrically. Do not connect any
RS-232 device to this connector. Doing so can result in damage to both the
device and the Macintosh LC.
Modem and Printer Ports
-----------------------
Pin Signal name Signal description
1 HSKo Handshake out
2 HSKi Handshake in/external clock
3 TXD- Transmit data -
4 GND Signal ground
5 RXD- Receive data -
6 TXD+ Transmit data +
7 GPi General purpose input*
8 RXD+ Receive data +
*Modem port only. Can be set in software to be a second external clock.
- Connector type: 8-pin minicircular
Disk Drive Port
---------------
Pin Signal name Signal description
1 GND Signal ground
2 GND Signal ground
3 GND Signal ground
4 GND Signal ground
5 -12v -12 volts DC
6 +5v +5 volts DC
7 +12v +12 volts DC
8 +12v +12 volts DC
9 NC No connection
1 PWM Motor speed control
11 PH0 Register select CA0
12 PH1 Register select CA1
13 PH2 Register select CA2
14 PH3 Register write strobe LSTRB
15 WRREQ/ Write request
16 SEL Register select line SEL
17 ENBL/ Drive enable
18 RD Read data
19 WR Write data
- Connector type: DB-19
Audio Jack for the Macintosh SE
-------------------------------
Pin Signal name Signal description
(Sleeve) GND Signal ground
(Tip) AUDIO .5 volt peak-to-peak
audio signal
- Connector type: Miniature mono phone plug
- The internal speaker is disabled when this port is in use.
Audio Jack for the Macintosh SE/30
----------------------------------
Pin Signal name Signal description
(Sleeve) GND Signal ground
(Ring) RIGHT .75 volt peak-to-peak audio
signal, right channel
(Tip) LEFT .75 volt peak-to-peak audio
signal, left channel
- Connector type: Stereo miniature phone plug
- The internal speaker is disabled when this port is in use.
-----------------------
Pin Signal name Signal description
1 ADB Data
2 NC Reserved
3 +5v +5 volts DC
4 GND Signal ground
- Connector type: 4-pin minicircular
- Total length of all cables not to exceed 16 feet (5 meters)
SCSI Port (25-pin)
------------------
Pin Signal name Signal description
1 REQ/ Request
2 MSG/ Message
3 I/O/ Input/Output
4 RST/ SCSI bus reset
5 ACK/ Acknowledge
6 BSY/ Busy
7 GND Signal ground
8 DB0/ Data bit 0
9 GND Signal ground
10 DB3/ Data bit 3
11 DB5/ Data bit 5
12 DB6/ Data bit 6
13 DB7/ Data bit 7
14 GND Signal ground
15 C/D/ Common/Data
16 GND Signal ground
17 ATN/ Attention
18 GND Signal ground
19 SEL/ Select
20 DBP/ Data parity
21 DB1/ Data bit 1
22 DB2/ Data bit 2
23 DB4/ Data bit 4
24 GND Signal ground
25 TPWR Terminator power
- Connector type: DB-25
- Total length of all cables not to exceed 20 feet (6 meters)
WARNING: The SCSI port uses the same type of connector as a standard RS-232,
DB-25 serial interface, but it is different electrically. Do not connect any
RS-232 device to this connector. Doing so can result in damage to both the
device and the Macintosh LC.
Modem and Printer Ports
-----------------------
Pin Signal name Signal description
1 HSKo Handshake out
2 HSKi Handshake in/external clock
3 TXD- Transmit data -
4 GND Signal ground
5 RXD- Receive data -
6 TXD+ Transmit data +
7 GPi General purpose input*
8 RXD+ Receive data +
*Modem port only. Can be set in software to be a second external clock.
- Connector type: 8-pin minicircular
Disk Drive Port
---------------
Pin Signal name Signal description
1 GND Signal ground
2 GND Signal ground
3 GND Signal ground
4 GND Signal ground
5 -12v -12 volts DC
6 +5v +5 volts DC
7 +12v +12 volts DC
8 +12v +12 volts DC
9 NC No connection
1 PWM Motor speed control
11 PH0 Register select CA0
12 PH1 Register select CA1
13 PH2 Register select CA2
14 PH3 Register write strobe LSTRB
15 WRREQ/ Write request
16 SEL Register select line SEL
17 ENBL/ Drive enable
18 RD Read data
19 WR Write data
- Connector type: DB-19
Audio Jack for the Macintosh SE
-------------------------------
Pin Signal name Signal description
(Sleeve) GND Signal ground
(Tip) AUDIO .5 volt peak-to-peak
audio signal
- Connector type: Miniature mono phone plug
- The internal speaker is disabled when this port is in use.
Audio Jack for the Macintosh SE/30
----------------------------------
Pin Signal name Signal description
(Sleeve) GND Signal ground
(Ring) RIGHT .75 volt peak-to-peak audio
signal, right channel
(Tip) LEFT .75 volt peak-to-peak audio
signal, left channel
- Connector type: Stereo miniature phone plug
- The internal speaker is disabled when this port is in use.