Modem Cables Macintosh (Mini DIN-8) Serial Connectors (Mac Plus and later) (This diagram is the connector on the end of a modem cable that you plug into your Mac.) Pin Name Description/Notes 1 HSKo Output Handshake (from Zilog 8530 DTR pin) 2 HSKi/Ext Clk Input Handshake (CTS) or TRxC (depends on 8530 mode) 3 TxD- Transmit Data line 4 Ground 5 RxD- Receive Data line 6 TxD+ Transmit Data line 7 GPi/DCD General Purpose Input (not all models) 8 RxD+ Receive Data line; ground this line to emulate RS232 Mac DIN-8 to MODEM - Hardware Handshaking Mac Modem (DB-25) 1 (HSKout) -> 4 (RTS) 2 (HSKin) <- 5 (CTS) 3 (TxD-) -> 2 (TxD) 4 (GND) <-> 7 (Signal Gnd) 5 (RxD-) <- 3 (RxD) 6 (TxD+) -- NONE 7 (GPi) <- 8 (DCD) - not currently used by ZTerm 8 (RxD+) <- 7 (Gnd) Note: This is my recommendation for the cable wiring. Pin 7 (GPi) is not currently used and I don’t know if any off-the-shelf cables have pin 7 connected. Some hardware handshake cables will have pin 20 (DTR) on the modem connected to Mac pin 1 (in addition to pin 4 RTS). This is OK but you MUST remember to configure the modem to ignore the DTR line. MacConnection is selling a cable labeled ‘Mac+ to MNP modem’ that is like this (pin 1 to 4 & 20 of the modem). Mac DIN-8 to MODEM - Typical Non-Hardware Handshaking Mac Modem (DB-25) 1 (HSKout) -> 20 (DTR) 2 (HSKin) <- 6 (CTS) & 8 (DCD) 3 (TxD-) -> 2 (TxD) 4 (GND) <-> 7 (Signal Gnd) 5 (RxD-) <- 3 (RxD) 6 (TxD+) -- NONE 7 (GPi) <- NONE 8 (RxD+) <- 7 (Gnd) Macintosh 512, 128 Serial Connectors (DB-9) (This diagram is the connector on the end of a modem cable that you plug into your Mac.) Pin Name Description/Notes 1 Ground 2 +5V See Hardware reference for power limits 3 Ground 4 TxD+ Transmit Data line 5 TxD– Transmit Data line 6 +12V See Hardware reference for power limits 7 HSK HandShaKe: CTS or TRxC, depends on Zilog 8530 mode 8 RxD+ Receive Data line; ground this line to emulate RS232 9 RxD– Receive Data line Mac 512, 128 (DB-9) to MODEM Mac Modem 1 (GND) <-> 1 (Gnd) 3 (GND) <-> 7 (Signal Gnd) 4 (TxD+) -- NONE 5 (TxD-) -> 2 (TxD) 6 (+12v) -> 20 (DTR) 7 (HSKin) <- 6 (CTS) & 8 (DCD) 8 (RxD+) <- 7 (Signal Gnd) 9 (RxD-) <- 3 (RxD)
Pin | Signal | Pin | Signal | Pin | Signal |
1 | T.M.D.S. Daten2- | 9 | T.M.D.S. Daten1- | 17 | T.M.D.S. Daten0- |
2 | T.M.D.S. Daten2+ | 10 | T.M.D.S. Daten1+ | 18 | T.M.D.S. Daten0+ |
3 | T.M.D.S. Daten2/4 Abschirmung | 11 | T.M.D.S. Daten1/3 Abschirmung | 19 | T.M.D.S. Daten0/5 Abschirmung |
4 | T.M.D.S. Daten4- | 12 | T.M.D.S. Daten3- | 20 | T.M.D.S. Daten5- |
5 | T.M.D.S. Daten4+ | 13 | T.M.D.S. Daten3+ | 21 | T.M.D.S. Daten5+ |
6 | DDC-Clock | 14 | +5V Strom | 22 | T.M.D.S. Clock-abschirmung |
7 | DDC-Daten | 15 | Erdung (für +5V) | 23 | T.M.D.S. Clock+ |
8 | Kein Anschluß | 16 | Hot Plug Detect | 24 | T.M.D.S. Clock- |