Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!crdgw1!beowulf!bownesrm From: bownesrm@beowulf.UUCP (Waiting for the Sun) Newsgroups: comp.sys.tandy Subject: Re: TRS80, Model 100 Portable Questions Message-ID: <1883@beowulf.UUCP> Date: 5 Mar 91 20:39:32 GMT Organization: Team Slime - Albany Division Lines: 101 ->1. There's a RAM OPTION socket inside the MODEL 100; can anyone tell -> me what chip(s) fit in this, and what extra capacity it/they -> will give me. It is for an 8K x 8 custom Static RAM carrier. This was an 8K x 8 ram built out of 4 2k x 8's mounted on a ceramic carrier. There are no standard SRAMS that will fit in this socket. You can however build your own carrier if sufficiently motivated. Pinout for the RAM array sockets are as follows: 1 a7 28 vdd 2 a6 27 a8 3 a5 26 a9 4 a4 25 WR* 5 a3 24 ce3* 6 a2 23 a10 7 a1 22 OE* 8 a0 21 ad7 9 ad0 20 ad6 10 ad1 19 ad5 11 ad2 18 ad4 12 gnd 17 ad3 13 ce0* 16 gnd 14 ce1* 15 ce2* The ce0-3 lines are chip select to each of the 2k x 8 rams. If you want to connect them to a 8k x 8 RAM you'll have to decode them back down into 2 address lines and a chip select decoder. Not tough logically, but it gets tight in the M100 case. ->2. There's a ROM OPTION socket as well; what would this be for, and -> was anything ever produced for it? Possibly the most used expansion capability of the machine. Traveling Software has (had?) several different option ROMS available. ->3. The BUS connector, what use is it? Used for connecting the Disk/Video interface to the M100. This little box gave you 80 x 24 video & 5 1/4" floppies. Was about $200.00 when they stopped selling it. But it was very useful if you could get one. ->4. What are the pin configurations for the phone plug and Cassete plug -> (and has anyone used them successfully outside the us) Cassette Plug: Pin# Signal Description 1 REM1 One side of start/stop switch/relay 2 GND ground 3 REM2 other side of start/stop switch/relay 4 RXC Speaker out from cassette. 5 TXC audio/mic into cassette 6 GND 7,8 N/C Phone plug: Pin # Signal Description 1 TL tip for aux phone unit. 2 GND ground 3 RXMD Recieve Modem Direct (ring) 4 RXM Recieve Modem (acoustic coupler) 5 TXM Transmit Modem (acoustic coupler) 6 Vdd power for acoustic coupler 7 TXMD Transmit Modem Direct (tip) 8 RP Ring Pulse (for aux phone unit) To convert a Model 100 from US modem standard to C.C.I.T.T. all that is needed is to disconnect pin 14 of the modem chip (m31, an MC14412) from Vdd (it is connected to pins 15 and 16 then to vdd through r46) and connect it to ground. This pin selects the 'type' for the modem chip. ->5. TELCOM -> (a). Can Telcom CALL using tones, not pulses? Yes, but I don't remember how. -> (b). Can anyone list all that you can change with the STAT -> command, and the options for each, i.e. which letter -> changes baud rate, parity, etc etc It's all in the manual, which, if you are missing, can be ordered through National Parts. ->6. BASIC -> What other M100 specific commands (like DATE$,Day,time,IPL) -> are there. Check "Hidden Powers of the Model 100" by cChristoper Morgan, ISBn 0-452-25578-3 Most of the above information came out of the Model 100 Service Manual, RS part # ms26-3801, which includes technical descriptions of all the LSI, schematics, troubleshooting, theory of operation for major sections, etc. It's about 100+ pages of very detailed technical information on the 100. Bob Bownes