Path: utzoo!attcan!uunet!lll-winken!csustan!csun!srhqla!denwa!bongo!julian From: julian@bongo.UUCP (julian macassey) Newsgroups: comp.sys.att Subject: Re: modular null modem pinout? Summary: RS-232 Pinouts (boring) Keywords: 386 <---> 3b2 direct Message-ID: <205@bongo.UUCP> Date: 16 May 89 02:11:34 GMT References: <433@bigbroth.UUCP> Organization: The Hole in the Wall Hollywood CA U.S.A. Lines: 168 In article <433@bigbroth.UUCP>, rk@bigbroth.UUCP (rohan kelley) writes: > I'm trying to make a direct connect between a bell tech 386/25 and > a 3b2/400. The port on the 386 is an ace intelligent port board > with 8 modular ports and on the 3b2 an enhanced port board. > > I'm trying to construct a modular null modem cable. This is the > wiring diagram I've come up with, but haven't tried it yet. Does > anybody know if this is correct? > > What I'm trying to say is: > > G 1 to 1 G > CTS 2 tie to 8 (plug) > TDXO 3 to 5 RXDO > DTR 4 to 6 DCD > RXDO 5 to 3 TDXO > DCD 6 to 4 DTR > G 7 to 7 G > RTS 8 tie to 2 (plug) > > Neither the 386 or 3b2 have DSR (RS232 pin 6) which is usually tied to > DTR. Is it needed? What you have is not recognisable by me. Here is my RS-232 memory jogger file. This may help some people. The Following are Various RS-232 Configurations. DB-25 25 Pin Std Connector Pin # 1 Ground (Protective Ground) (Optional) 2 Transmit Data (TXD) 3 Receive Data (RXD) 4 Request To Send (RTS) 5 Clear To Send (CTS) 6 Data Set Ready (DSR) 7 Ground (Signal Ground) 8 Data Carrier Detect (DCD) 9 + Testing Voltage 10 - Testing Voltage 11 No Connection 12 Speed Mode Indication (CI) 13 No Connection 14 No Connection 15 Transmit Clock 16 No Connection 17 Receive Clock 18 Make Busy/Analog Loop (CN) 19 No Connection 20 Data Terminal Ready (DTR) 21 Remote Digital Loop (RDL) 22 Ring Indicator (CE) 23 Speed Select - Originate (CH) 24 Clock Out 25 Test Mode (TM) DB-9 9 Pin Std Connector Pin # 1 Data Carrier Detect (DCD) 2 Receive Data (RXD) 3 Transmit Data (TXD) 4 Data Terminal Ready (DTR) 5 Ground (GND) 6 Data Set Ready (DSR) 7 Request To Send (RTS) 8 Clear To Send (CTS) 9 Ring Indicator (CE) (RI) DB9 to DB25 RS-232 Adaptor DB9 DB25 1 DCD 8 2 RXD 3 3 TXD 2 4 DTR 20 5 GND 7 6 DSR 6 7 RTS 4 8 CTS 5 9 RI 22 SHELL GND 1 Standard RS-232 Cable DB25 DB25 1 GND 1 2 TXD 2 3 RXD 3 4 RTS 4 5 CTS 5 6 DSR 6 7 GND 7 8 DCD 8 20 DTR 20 22 RING IND 22 (optional for answer modems) Minimum RS-232 Cable (OK for some slow devices) DB25 DB25 2 TXD 2 3 RXD 3 7 GND 7 Null Modem Simple (Using DB25 Connectors, see above for conversion to DB9) This Null Modem connector is equivelent to Black Box Model ME202B. It is used for conecting terminals to mainframes and UUCP connections. A B 1---------1 2---------3 3---------2 7---------7 4| 4| Note: | Means, pins are jumpered 5| 5| together. - means pins wired to other connector. 6| 6| 8| 8| 20| 20| Null Modem with control (With this cable, turning off a terminal should disconnect the line. recommended for use with terminals logged into mainframes.) A B 1---------1 2---------3 3---------2 4---------5 Note: | Means, pins are jumpered 5---------4 together. - means pins wired 7---------7 to other connector. 6|-------20 8| 20--------|6 |8 References: AT&T Unix-PC Communications Management Manual. Toshiba T1100P Users Manual EIA RS-232C (Oct 1969) Bell System Tech Ref Data Set 212A END -- Julian Macassey, n6are julian@bongo ucla-an!denwa!bongo!julian n6are@wb6ymh (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495