diff --git a/ROM2/chime.h b/ROM2/chime.h
index 88e8b151407a1c2709737b0178af85215bb71901..bd93ab49b92c0e04804399e76e2dba1445ec618a 100644
--- a/ROM2/chime.h
+++ b/ROM2/chime.h
@@ -10,6 +10,7 @@ extern volatile u8 chime_count;
 
 /* outside world interface */
 extern inline void chime_start() { chime_count = CHIME_TIME; }
+extern inline void chime_for(u8 time) { chime_count = time; }
 
 void chime(); /* RTI interrupt */
 
diff --git a/ROM2/helpers.c b/ROM2/helpers.c
index 5f0da09c9770b2706e9f61bec11213d25cd47900..ad52123b97a39a1eed528036a861948c5344c75a 100644
--- a/ROM2/helpers.c
+++ b/ROM2/helpers.c
@@ -10,12 +10,13 @@ void delay(u16 ms) {
 	 * parsing C -> asm, but before asm -> machine code.
 	 */
 	//asm volatile ("pshx\npsha\npshb\n"); /* save registers */
-	asm volatile ("ldx %0\n" :: "m" (ms));
+	asm volatile ("ldx %0\n" :: "m" (ms) : "x");
 	asm volatile (
 		"delay_loop:\n"
 		"	dex\n"                        /* 3 */
 		"	beq delay_out\n"              /* 3 */
-		"	ldd #327\n"                   /* 3 */
+		//"	ldd #327\n"                   /* 3 */
+		"	ldd #150\n"                   /* 3 */
 		"delay_inner_loop:\n" /* 15 cycles each */
 		"	cpd #0x0000\n"                /* 5 */
 		"	beq delay_inner_loop_end\n"   /* 3 */
@@ -23,7 +24,7 @@ void delay(u16 ms) {
 		"	bra delay_inner_loop\n"       /* 3 */
 		"delay_inner_loop_end:\n"
 		"	bra delay_loop\n"             /* 3 */
-		"delay_out:\n");
+		"delay_out:\n" ::: "x", "d");
 		/*"	pulb\n"
 		"	pula\n"
 		"	pulx\n");*/
@@ -35,6 +36,16 @@ void my_strncpy(char* dst, char* src, u8 max_size) {
 	if (src[i] == 0 && i < max_size) dst[i] = 0; /* null terminator */
 }
 
+bool my_strncmp(char* a, char* b, u8 len) {
+	u8 i;
+	for (i = 0; i < len; i++) {
+		if (*a != *b) return 0;
+		a++;
+		b++;
+	}
+	return 1;
+}
+
 void my_memcpy(char* dst, char* src, u8 size) {
 	u8 i = 0;
 	for (i = 0; i < size; i++) dst[i] = src[i];
diff --git a/ROM2/main_basic.c b/ROM2/main_basic.c
index 44e09448cdd7928d69eba988c6e331b3df280425..5c35aab32751094018ce99b0d0bcfdecbdfdc68a 100644
--- a/ROM2/main_basic.c
+++ b/ROM2/main_basic.c
@@ -4,6 +4,8 @@
  * and snacks.
  */
 
+#define VERSION_STRING "R 20040622"
+
 #include "display_basic.h"
 #include "keypad.h"
 #include "chime.h"
@@ -12,39 +14,90 @@
 #include "sci.h"
 #include "vend.h"
 
-void motor_reply(char* slotptr, u8 code) {
+u8 last_standalone;
+u8 last_switch_input;
+u8 last_misc_input;
+u16 last_coin_value;
+bool last_door_open;
+char display_buf[11];
+/* cur_motor[0] is 0 for nothing, or 1..10, or 0xff to say redraw.
+ * cur_motor[1] is 0..9 and only meaningful is cur_motor[0] != 0. */
+u8 cur_motor[2];
+
+bool check_standalone() {
+	if (is_standalone()) {
+		send_string("011 In standalone mode. Function disabled." CRLF);
+		return 1;
+	}
+	return 0;
+}
+
+void unknown_command() {
+	send_string("012 Unknown command. Type HELP for help." CRLF);
+}
+
+void motor_reply(u8 code) {
 	/* returns a message of the form MXYY - X is return code, YY is motor */
-	wait_for_tx_free();
-	sci_tx_buf[0] = 'M';
-	sci_tx_buf[1] = code + '0';
-	sci_tx_buf[2] = *slotptr;
-	sci_tx_buf[3] = *(slotptr+1);
-	sci_tx_buf[4] = '\n';
-	sci_tx_buf[5] = 0;
-	send_packet();
+	switch (code) {
+		case MOTOR_SUCCESS:
+			send_string("100 Vend successful." CRLF);
+			break;
+		case MOTOR_NOSLOT:
+			send_string("151 No motor there." CRLF);
+			break;
+		case MOTOR_CURRENT_FAIL:
+			send_string("152 Over current." CRLF);
+			break;
+		case MOTOR_HOME_FAIL:
+			send_string("153 Home sensors failing." CRLF);
+			break;
+		default:
+			send_string("159 Unknown motor error." CRLF);
+	}
 }
 
 void dispense_something() {
 	/* process a message VXX in sci_rx_buf where XX is motor number */
 	u8 slot;
 
+	if (check_standalone()) return;
+
+	if (my_strncmp("ALL", (char*)sci_rx_buf+1, 3)) {
+		char motor[3];
+		motor[2] = '\0';
+		send_string("102 Vend all motors starting." CRLF);
+		for (motor[0] = '0'; motor[0] <= '9'; motor[0]++) {
+			for (motor[1] = '0'; motor[1] <= '9'; motor[1]++) {
+				send_string("101 Vending ");
+				send_string(motor);
+				send_string(CRLF);
+				motor_reply(dispense_motor(motor[0]*10+motor[1]));
+			}
+		}
+		send_string("102 Vend all motors complete." CRLF);
+		return;
+	}
+
 	if ((sci_rx_buf[1] < '0') || (sci_rx_buf[1] > '9') ||
 		(sci_rx_buf[2] < '0') || (sci_rx_buf[2] > '9')) {
 		sci_rx_buf[1] = sci_rx_buf[2] = '0';
-		motor_reply((char*)&sci_rx_buf[1], MOTOR_NOSLOT);
+		motor_reply(MOTOR_NOSLOT);
 		return;
 	}
 
 	slot = (sci_rx_buf[1] - '0') * 10;
 	slot += sci_rx_buf[2] - '0';
 
-	motor_reply((char*)&sci_rx_buf[1], dispense_motor(slot));
+	motor_reply(dispense_motor(slot));
 }
 
 void write_to_display() {
-	/* process a message in the form DXXXXXXXXXXX to send to display */
+	/* process a message in the form DXXXXXXXXXX to send to display */
 	u8 i;
-	char buf[10];
+	char buf[11];
+
+	if (check_standalone()) return;
+
 	for (i = 0; i < 10; i++)
 		if (sci_rx_buf[i+1])
 			buf[i] = sci_rx_buf[i+1];
@@ -53,13 +106,13 @@ void write_to_display() {
 
 	for (; i < 10; i++) /* pad the rest out with spaces */
 		buf[i] = ' ';
+	buf[i] = '\0';
 
 	set_msg(buf);
-	send_ack();
+	send_string("300 Written." CRLF);
 }
 
 void send_balance() {
-	wait_for_tx_free();
 	sci_tx_buf[0] = 'C';
 	sci_tx_buf[1] = have_change?'0':'1';
 	sci_tx_buf[2] = (coin_value/10000)%10;
@@ -67,9 +120,8 @@ void send_balance() {
 	sci_tx_buf[4] = (coin_value/100)%10;
 	sci_tx_buf[5] = (coin_value/10)%10;
 	sci_tx_buf[6] = coin_value%10;
-	sci_tx_buf[7] = '\n';
 	sci_tx_buf[8] = 0;
-	send_packet();
+	send_buffer(1);
 }
 
 void give_change() {
@@ -94,52 +146,174 @@ void give_change() {
 
 void send_keypress(u8 key) {
 	/* send a packet of the form KX with X being the key, or R for reset */
-	wait_for_tx_free();
-	sci_tx_buf[0] = 'K';
-	if (key == KEY_RESET)
-		sci_tx_buf[1] = 'R';
-	else
-		sci_tx_buf[1] = (key%10)+'0';
-	sci_tx_buf[2] = '\n';
-	sci_tx_buf[3] = 0;
-	send_packet();
+	if (is_standalone()) return;
+
+	sci_tx_buf[0] = '2';
+	if (key == KEY_RESET) {
+		sci_tx_buf[1] = '1';
+		sci_tx_buf[2] = '1';
+	} else {
+		sci_tx_buf[1] = '0';
+		sci_tx_buf[2] = (key%10)+'0';
+	}
+	sci_tx_buf[3] = '\0';
+	send_buffer(0);
+	send_string(" key." CRLF);
 }
 
 void send_door_msg(bool open) {
-	wait_for_tx_free();
-	sci_tx_buf[0] = 'D';
-	sci_tx_buf[1] = open?'1':'0';
-	sci_tx_buf[2] = '\n';
-	sci_tx_buf[3] = 0;
-	send_packet();
+	if (is_standalone()) return;
+	sci_tx_buf[0] = '4';
+	sci_tx_buf[1] = '0';
+	sci_tx_buf[2] = open?'1':'0';
+	send_buffer(0);
+	if (open)
+		send_string(" door open." CRLF);
+	else
+		send_string(" door closed." CRLF);
+}
+
+u8 hexchar2u8(char b) {
+	if (b >= '0' && b <= '9') return b-'0';
+	if (b >= 'a' && b <= 'f') return b-'a'+0x0a;
+	if (b >= 'A' && b <= 'F') return b-'A'+0x0a;
+	return 0;
+}
+
+char nibble2hexchar(u8 b) {
+	if (b <= 9) return b+'0';
+	if (b >= 10 && b <= 15) return b+'A';
+	return 'X';
+}
+
+u8 hex2u8(char msb, char lsb) {
+	return (hexchar2u8(msb) << 4) + hexchar2u8(lsb);
+}
+
+static char hexconv_buf[3];
+char* u82hex(u8 a) {
+	hexconv_buf[0] = nibble2hexchar((a&0xf0) >> 4);
+	hexconv_buf[1] = nibble2hexchar(a&0x0f);
+	hexconv_buf[2] = '\0';
+	return hexconv_buf;
 }
 
 void do_chime() {
-	chime_start();
-	send_ack();
+	if (check_standalone()) return;
+	if (sci_rx_buf[1] == '\0')
+		chime_start();
+	else if (sci_rx_buf[2] != '\0' && sci_rx_buf[3] == '\0')
+		chime_start(hex2u8(sci_rx_buf[1], sci_rx_buf[2]));
+	else {
+		send_string("510 Unknown chime duration." CRLF);
+		return;
+	}
+	send_string("500 Chimed." CRLF);
+}
+
+void print_switches(u8 prompted) {
+	if (prompted)
+		send_string("600 ");
+	else
+		send_string("610 ");
+	send_string(u82hex(misc_input));
+	send_string(" ");
+	send_string(u82hex(switch_input));
+	send_string(CRLF);
 }
 
 void ping_pong() {
 	/* make sure it's really a ping */
-	if (sci_rx_buf[1] != 'I' ||
-		sci_rx_buf[2] != 'N' ||
-		sci_rx_buf[3] != 'G' ||
-		sci_rx_buf[4] != '\0') {
-		send_nack();
+	if (!my_strncmp("ING", (char*)sci_rx_buf+1, 3)) {
+		unknown_command();
 		return;
 	}
 	/* respond with ack & pong */
-	wait_for_tx_free();
-	my_strncpy(sci_tx_buf, "PONG\n", BUFFER_LEN);
-	send_packet();
+	send_string("000 PONG!" CRLF);
 }
 
-u16 last_coin_value;
-bool last_door_open;
-char display_buf[11];
-/* cur_motor[0] is 0 for nothing, or 1..10, or 0xff to say redraw.
- * cur_motor[1] is 0..9 and only meaningful is cur_motor[0] != 0. */
-u8 cur_motor[2];
+void send_prompt() {
+	send_string(is_standalone()?"$ ":"# ");
+}
+
+void about() {
+	if (!my_strncmp("BOUT", (char*)sci_rx_buf+1, 4)) {
+		unknown_command();
+		return;
+	}
+	send_string(
+		"-----------------------------------------------------------------" CRLF
+		"    ROM2 (C) 2004 Bernard Blackham <dagobah@ucc.gu.uwa.edu.au>" CRLF
+		"-----------------------------------------------------------------" CRLF
+		"                                        Revision " VERSION_STRING CRLF
+		"" CRLF
+		"   This snack machine was brought to you by " CRLF
+		"    Bernard Blackham" CRLF
+		"    Mark Tearle" CRLF
+		"    Harry McNally" CRLF
+		"    Michal Gornisiewicz" CRLF
+		"    and others." CRLF
+		"" CRLF
+		" Another UCC project in action.         http://www.ucc.asn.au/" CRLF
+	);
+}
+
+void set_echo() {
+	if (my_strncmp("CHO ON", (char*)sci_rx_buf+1, 6))
+		sci_echo = 1;
+	else if (my_strncmp("CHO OFF", (char*)sci_rx_buf+1, 7))
+		sci_echo = 0;
+	else
+		unknown_command();
+}
+
+void moo() {
+	if (!my_strncmp("OO", (char*)sci_rx_buf+1, 2)) {
+		unknown_command();
+		return;
+	}
+	send_string(
+"       ____________" CRLF
+"       |__________|" CRLF
+"      /           /\\" CRLF
+"     /  U C C    /  \\" CRLF
+"    /___________/___/|" CRLF
+"    |          |     |" CRLF
+"    |  ==\\ /== |     |" CRLF
+"    |   O   O  | \\ \\ |" CRLF
+"    |     <    |  \\ \\|" CRLF
+"   /|          |   \\ \\" CRLF
+"  / |  \\_____/ |   / /" CRLF
+" / /|          |  / /|" CRLF
+"/||\\|          | /||\\/" CRLF
+"    -------------|   " CRLF
+"        | |    | | " CRLF
+"       <__/    \\__>" CRLF
+	);
+}
+
+void help() {
+	send_string(
+		"Valid commands are:" CRLF
+		" ABOUT         ROM information" CRLF
+		" PING          pongs" CRLF
+		" ECHO {ON|OFF} turn echo on or off" CRLF
+		" Vnn           vend an item" CRLF
+		" VALL          vend all items" CRLF
+		" DXXXXXXXXXX   show a message on the display" CRLF
+		" B[nn]         beep for a duration nn (optional)" CRLF
+		" S[...]        query all internal switch states" CRLF
+		" H[...]        this help screen" CRLF
+		"Comments start with a #" CRLF
+	);
+}
+
+void quit() {
+	if (my_strncmp("UIT", (char*)sci_rx_buf+1, 3))
+		send_string("013 You can't quit you doofus." CRLF);
+	else
+		unknown_command();
+}
 
 int main() {
 	u8 i;
@@ -153,7 +327,7 @@ int main() {
 	_io_ports[M6811_DDRD] = 0x3e;
 	_io_ports[M6811_SPCR] = M6811_MSTR | M6811_SPR1;
 	set_misc_output(0x00);
-	
+
 	display_init();
 	set_msg(" HELLO    ");
 	delay(1000);
@@ -176,10 +350,18 @@ int main() {
 
 	chime_start();
 
-	my_strncpy(sci_tx_buf, "5N4X0RZRUS\n", BUFFER_LEN);
-	send_packet();
+	send_string("5N4X0RZ R US" CRLF);
 	
-	cur_motor[0] = 0xff;
+	last_standalone = is_standalone();
+	if (last_standalone)
+		cur_motor[0] = 0xff;
+	else
+		cur_motor[0] = 0;
+	send_prompt();
+
+	last_switch_input = switch_input;
+	last_misc_input = misc_input;
+
 	while(1) {
 		if (cur_motor[0] == 0xff) { /* signal to say redraw screen */
 			set_msg("*5N4X0RZ* ");
@@ -193,8 +375,36 @@ int main() {
 			set_msg(last_door_open?"DOOR OPEN ":"DOOR CLOSE");
 		}
 
+		if (last_standalone != is_standalone()) {
+			/* somebody flicked the standalone switch */
+			msg_clr();
+			send_string(CRLF);
+			send_prompt();
+			last_standalone = is_standalone();
+		}
+
+		if (last_misc_input != misc_input) {
+			print_switches(0);
+			last_misc_input = misc_input;
+		}
+
+		if (last_switch_input != switch_input) {
+			print_switches(0);
+			last_switch_input = switch_input;
+		}
+
 		if (sci_have_packet) {
 			switch (sci_rx_buf[0]) {
+				case '\0':
+				case '#':
+					send_string(CRLF);
+					break;
+				case 'E':
+					set_echo();
+					break;
+				case 'H':
+					help();
+					break;
 				case 'V':
 					dispense_something();
 					break;
@@ -204,66 +414,75 @@ int main() {
 				case 'B': 
 					do_chime();
 					break;
-				case 'U':
-					send_balance();
-					break;
-				case 'G':
-					give_change();
-					break;
 				case 'P':
 					ping_pong();
 					break;
+				case 'A':
+					about();
+					break;
+				case 'S':
+					print_switches(1);
+					break;
+				case 'M':
+					moo();
+					break;
+				case 'Q':
+					quit();
+					break;
 				default:
 					// shurg
-					send_nack();
+					unknown_command();
 					break;
 			}
 			msg_clr();
+			send_prompt();
 		}
 
 		keypad_read();
 		if (keypad_pressed()) {
-			if (last_key == KEY_RESET) {
-				cur_motor[0] = 0xff;
-			} else {
-				if (cur_motor[0]) {
-					u8 motor_num;
-					cur_motor[1] = last_key%10;
-					display_buf[1] = cur_motor[1]+'0';
-					set_msg(display_buf);
-
-					motor_num = cur_motor[0]%10;
-					motor_num *= 10;
-					motor_num += cur_motor[1];
-					switch (dispense_motor(motor_num)) {
-						case MOTOR_HOME_FAIL:
-							set_msg(" HOME FAIL ");
-							break;
-						case MOTOR_CURRENT_FAIL:
-							set_msg(" OVER CRNT ");
-							break;
-						case MOTOR_SUCCESS:
-							set_msg("THANK  YOU");
-							break;
-						case MOTOR_NOSLOT:
-							set_msg(" NO MOTOR ");
-							break;
-						default:
-							set_msg("ERRRRRRRR?");
-							break;
-					}
-
-					display_buf[0] = ' ';
-					display_buf[1] = ' ';
+			if (is_standalone()) {
+				if (last_key == KEY_RESET) {
 					cur_motor[0] = 0xff;
-					delay(500);
 				} else {
-					cur_motor[0] = last_key;
-					display_buf[0] = (last_key%10)+'0';
-					set_msg(display_buf);
+					if (cur_motor[0]) {
+						u8 motor_num;
+						cur_motor[1] = last_key%10;
+						display_buf[1] = cur_motor[1]+'0';
+						set_msg(display_buf);
+
+						motor_num = cur_motor[0]%10;
+						motor_num *= 10;
+						motor_num += cur_motor[1];
+						switch (dispense_motor(motor_num)) {
+							case MOTOR_HOME_FAIL:
+								set_msg(" HOME FAIL ");
+								break;
+							case MOTOR_CURRENT_FAIL:
+								set_msg(" OVER CRNT ");
+								break;
+							case MOTOR_SUCCESS:
+								set_msg("THANK  YOU");
+								break;
+							case MOTOR_NOSLOT:
+								set_msg(" NO MOTOR ");
+								break;
+							default:
+								set_msg("ERRRRRRRR?");
+								break;
+						}
+
+						display_buf[0] = ' ';
+						display_buf[1] = ' ';
+						cur_motor[0] = 0xff;
+						delay(500);
+					} else {
+						cur_motor[0] = last_key;
+						display_buf[0] = (last_key%10)+'0';
+						set_msg(display_buf);
+					}
 				}
-			}
-			send_keypress(last_key);
+			} else
+				send_keypress(last_key);
 		}
 
 		/*
diff --git a/ROM2/motors.c b/ROM2/motors.c
index e7cb6b50db87f90bf36d531d081b34f9e76e484f..efed7cc73a85255be7cdacc015db394cc2b4c104 100644
--- a/ROM2/motors.c
+++ b/ROM2/motors.c
@@ -36,7 +36,7 @@ void motor_shift_send(u8 data) {
 	}
 }
 
-void motor_on(u8 slot) {
+void set_motor(u8 slot) {
 	u8 row, col;
 	row = slot%10;
 	col = slot/10;
@@ -61,30 +61,38 @@ void motor_on(u8 slot) {
 	motor_shift_send(1 << (row-1)); /* rows from 1..8 here */
 
 	bclr((void*)&_io_ports[M6811_PORTA], PORTA_MOTOR_CLOCK);
+}
+
+void motor_start() {
 	bclr_changer_output(A3000_MOTOR_ROW_DISABLE);
 }
 
-void motors_off() {
+void motor_pause() {
+	bset_changer_output(A3000_MOTOR_ROW_DISABLE);
+}
+
+void motor_stop() {
 	bset_changer_output(A3000_MOTOR_ROW_DISABLE);
-	delay(10); /* XXX cf motors_off */
 	bset((void*)&_io_ports[M6811_PORTA], PORTA_MOTOR_COL_DISABLE);
 	bclr_misc_output(A3800_MOTOR_COL8_ENABLE | A3800_MOTOR_COL9_ENABLE);
 }
 
 bool motor_here(u8 slot) {
 	u8 i, c = 0;
+	set_motor(slot);
 	for (i=0; i < 8; i++) {
-		motor_on(slot);
+		motor_start();
 		delay(5);
 		if ((_io_ports[M6811_PORTE] & PORTE_MOTOR_OVERVOLTAGE) == 0) {
 			c++;
 			if (c == 3) {
-				motors_off();
+				motor_stop();
 				return 1;
 			}
 		}
-		motors_off();
+		motor_pause();
 	}
+	motor_stop();
 	return 0;
 }
 
@@ -98,14 +106,15 @@ bool start_motor(u8 slot) {
 	u8 r = slot%10;
 	if (r >= 5) r--; 
 	r = 1 << (r-1);
-	motor_on(slot);
-	delay(100);
+	set_motor(slot);
+	motor_start();
+	delay(50);
 	for (i = 0; i < 1000; i++) {
 		if ((home_sensors & r) != 0) return 1;
 		delay(1);
 	}
 	/* it never left */
-	motors_off();
+	motor_stop();
 	return 0;
 }
 
@@ -139,15 +148,15 @@ bool motor_overcurrent() {
 u8 dispense_motor(u8 slot) {
 	if (!is_motor(slot)) return MOTOR_NOSLOT;
 	if (!start_motor(slot)) return MOTOR_HOME_FAIL;
+	delay(100);
 
 	while (1) {
 		if (motor_overcurrent()) {
-			motors_off();
+			motor_stop();
 			return MOTOR_CURRENT_FAIL;
 		}
-		/* something should call motor_here? */
 		if (back_home(slot)) {
-			motors_off();
+			motor_stop();
 			return MOTOR_SUCCESS;
 		}
 	}
diff --git a/ROM2/sci.c b/ROM2/sci.c
index 668e865d646e09a02dc0c18ca74aa0523a08a1de..d7c9f287df6f4c84918681b88b159855b6ddaac0 100644
--- a/ROM2/sci.c
+++ b/ROM2/sci.c
@@ -5,6 +5,7 @@ char sci_tx_buf[BUFFER_LEN];
 volatile char sci_rx_buf[BUFFER_LEN];
 volatile bool sci_have_packet;
 volatile u8 sci_rx_buf_ptr;
+volatile bool sci_echo;
 
 void sci_init() {
 	/* assumes clock of 4.91Mhz */
@@ -18,9 +19,10 @@ void sci_init() {
 
 	sci_have_packet = 0;
 	sci_rx_buf_ptr = 0;
+	sci_echo = 0;
 }
 
-void send_packet() {
+void send_buffer(bool crlf) {
 	char* c;
 	for (c = sci_tx_buf; *c; c++) {
 		/* wait for TX ready */
@@ -29,28 +31,44 @@ void send_packet() {
 		/* send byte */
 		_io_ports[M6811_SCDR] = *c;
 	}
+	if (!crlf) return;
+	/* send CRLF */
+	while (!(_io_ports[M6811_SCSR] & M6811_TDRE));
+	_io_ports[M6811_SCDR] = '\r';
+	while (!(_io_ports[M6811_SCSR] & M6811_TDRE));
+	_io_ports[M6811_SCDR] = '\n';
+}
+
+void send_string(char* c) {
+	for (; *c; c++) {
+		while (!(_io_ports[M6811_SCSR] & M6811_TDRE)); /* wait for TX ready */
+		_io_ports[M6811_SCDR] = *c; /* send byte */
+	}
 }
 
 void sci_rx_int() {
+	char buf = _io_ports[M6811_SCDR];
+	if (sci_echo) {
+		while (!(_io_ports[M6811_SCSR] & M6811_TDRE)); /* wait for TX ready */
+		_io_ports[M6811_SCDR] = buf; /* send byte */
+	}
+
 	/* XXX FIXME we should do something about errors. nack? */
 	if (sci_have_packet) {
 		/* overrun :( */
-		_io_ports[M6811_SCDR]; /* read it anyway */
 		return;
 	}
-	sci_rx_buf[sci_rx_buf_ptr] = _io_ports[M6811_SCDR];
-	if (sci_rx_buf[sci_rx_buf_ptr] == '\n' ||
-			sci_rx_buf[sci_rx_buf_ptr] == '\r') {
-		if (sci_rx_buf_ptr == 0) return; /* we've read a blank packet in */
+	sci_rx_buf[sci_rx_buf_ptr] = buf;
+
+	if (buf == '\n' || buf == '\r') {
 		sci_rx_buf[sci_rx_buf_ptr] = '\0';
 		sci_have_packet = 1;
-		sci_rx_buf_ptr = 0;
 	}
-	sci_rx_buf_ptr++;
-	if (sci_rx_buf_ptr >= BUFFER_LEN) {
-		sci_rx_buf[BUFFER_LEN] = '\0'; /* this is as much as we could fit */
-		sci_have_packet = 1;
-		sci_rx_buf_ptr = 0;
+
+	if (sci_rx_buf_ptr+1 < BUFFER_LEN)
+		sci_rx_buf_ptr++;
+	else {
+		sci_rx_buf[BUFFER_LEN-1] = '\0'; /* this is as much as we could fit */
 	}
 }
 
@@ -67,11 +85,9 @@ void msg_clr() {
 }
 
 void send_ack() {
-	my_strncpy(sci_tx_buf, "!\n", BUFFER_LEN);
-	send_packet();
+	send_string("!" CRLF);
 }
 
 void send_nack() {
-	my_strncpy(sci_tx_buf, "?\n", BUFFER_LEN);
-	send_packet();
+	send_string("?" CRLF);
 }
diff --git a/ROM2/sci.h b/ROM2/sci.h
index 4b3a6d13d261ee22e70ce1d8f80e80da70862749..0db4b6408f541d55c4e426aa290dff09769784c3 100644
--- a/ROM2/sci.h
+++ b/ROM2/sci.h
@@ -4,10 +4,12 @@
 #include "vend.h"
 
 #define BUFFER_LEN 12
+#define CRLF "\r\n"
 
 void sci_init();
 void msg_clr();
-void send_packet();
+void send_buffer(bool crlf);
+void send_string(char* s);
 void send_ack();
 void send_nack();
 #define wait_for_tx_free() do { } while(0)
@@ -15,5 +17,6 @@ void send_nack();
 extern char sci_tx_buf[BUFFER_LEN];
 extern volatile char sci_rx_buf[BUFFER_LEN];
 extern volatile u8 sci_have_packet;
+extern volatile bool sci_echo;
 
 #endif /* _SCI_H_ */
diff --git a/ROM2/vend.h b/ROM2/vend.h
index 17ba674d1fd88c2deee12ec3b8692bde5283c997..460aa71169a3291e8805f19e69696185701f8f2f 100644
--- a/ROM2/vend.h
+++ b/ROM2/vend.h
@@ -26,11 +26,14 @@ extern volatile u8 _misc_input;
 extern volatile u8 _home_sensors;
 #define home_sensors _home_sensors
 
+#define is_standalone() (misc_input & 0x01) /* DIP sw 1 */
+
 extern u16 _stack;
 
 /******* from helpers.c *******/
 void delay(u16 ms);
 void my_strncpy(char* dst, char* src, u8 max_size); /* for null-term strings */
+bool my_strncmp(char* a, char* b, u8 len);
 void my_memcpy(char* dst, char* src, u8 size);
 
 /******** Some meaningful bits ******/