Schematic · 2022
Mike Douglas, *60ma Teletype Loop Driver*, schematic Rev A, April 2022 (regenerative snubber: T2 low side, D3 into C1/C2, U1 solid-state relay dumps them at mark; T1/L1/D2 optional boost)
R1—50 J3 D1 15vde KY R2 a y o3 pote JL A a en eee =) O for PM 150 for HM R4—560 7 R11 1K Selector Magnet 1/4” Phone Jack Power i" U3 \Z~| veceteenes bvd 15vdc : © Vin Vout ver Vec U1 t 8 ~—s Gnd ~~ 15vde C5 110 C6 0.1 g L1 100uh eee D2 D3 8 - N | RC2 = > < T1 RS—232 Rrc1}2 | C1 {1.0 J4 seussteee 4 R5—220 3 C2]1.0 TXD: @> TXD(RAO) ; Handshake ; o— pao RA5|2 L— Vec RJ-—14 U2 VY Modular Jack 15vde D4 | 7 : R7—10K _ TTY Keyboard RXD | 7|C2IN3— 3 RO-1K CF y : (RC3) RA4 -—— 1/4” Phone Jack D5 6310.1 ; R10—330 Gnd C20UT(RC4) 5 CCP1(RC5) 12 RXD(RA1) JS Vec ICSP_ Data}13 u Vec (RAO) AFSK Audio —_——_ SFeat) 6 Programming Header 1/8” Phone Jack VW C470.1 14 Note: ICSP pins shared elsewhere Gnd . . . Pins 3-5 can be option jumper RA3)V| VW (RA3)Vpp Looking into the modular jack on the PCB with hook down "Ground "R’eceive data into the adapter ‘T’ransmit data from the adapter ’"H’andshake line from the adapter Connections for DB—9 DTE (e.g., PC) G — 5 (Gnd) R — 3 (Xmt from PC) T — 2 (Rev to PC) H — 8 (CTS to PC) Connections for DB-—25 DCE G - 7 (Gnd) — 3 (Xmt from DCE) — 2 (Rev to DCE) R ; H — 4 (CTS to DCE) 60ma Teletype Loop Driver (Rev A, Apr 2022) Mike Douglas