diff --git a/artiq/test/coredevice/test_analyzer.py b/artiq/test/coredevice/test_analyzer.py
index b607ecc36..f28fa1cda 100644
--- a/artiq/test/coredevice/test_analyzer.py
+++ b/artiq/test/coredevice/test_analyzer.py
@@ -6,18 +6,17 @@ from artiq.test.hardware_testbench import ExperimentCase
 class CreateTTLPulse(EnvExperiment):
     def build(self):
         self.setattr_device("core")
-        self.setattr_device("ttl_inout")
+        self.setattr_device("loop_in")
+        self.setattr_device("loop_out")
 
     @kernel
     def run(self):
-        self.ttl_inout.output()
-        delay_mu(100)
         with parallel:
-            self.ttl_inout.gate_both_mu(1200)
+            self.loop_in.gate_both_mu(1200)
             with sequential:
                 delay_mu(100)
-                self.ttl_inout.pulse_mu(1000)
-        self.ttl_inout.count()
+                self.loop_out.pulse_mu(1000)
+        self.loop_in.count()
 
 
 class AnalyzerTest(ExperimentCase):
diff --git a/artiq/test/coredevice/test_rtio.py b/artiq/test/coredevice/test_rtio.py
index 1bccf6e42..ba05b8f73 100644
--- a/artiq/test/coredevice/test_rtio.py
+++ b/artiq/test/coredevice/test_rtio.py
@@ -20,7 +20,7 @@ class RTT(EnvExperiment):
     def run(self):
         self.ttl_inout.output()
         delay(1*us)
-        with parallel:
+        with interleave:
             # make sure not to send two commands into the same RTIO
             # channel with the same timestamp
             self.ttl_inout.gate_rising(5*us)
@@ -101,28 +101,6 @@ class Watchdog(EnvExperiment):
                 pass
 
 
-class LoopbackCount(EnvExperiment):
-    def build(self):
-        self.setattr_device("core")
-        self.setattr_device("ttl_inout")
-        self.setattr_argument("npulses")
-
-    def set_count(self, count):
-        self.set_dataset("count", count)
-
-    @kernel
-    def run(self):
-        self.ttl_inout.output()
-        delay(5*us)
-        with parallel:
-            self.ttl_inout.gate_rising(10*us)
-            with sequential:
-                for i in range(self.npulses):
-                    delay(25*ns)
-                    self.ttl_inout.pulse(25*ns)
-        self.set_dataset("count", self.ttl_inout.count())
-
-
 class Underflow(EnvExperiment):
     def build(self):
         self.setattr_device("core")
@@ -185,17 +163,6 @@ class Handover(EnvExperiment):
 
 
 class CoredeviceTest(ExperimentCase):
-    @unittest.skipUnless(artiq_low_latency,
-                         "timings are dependent on CPU load and network conditions")
-    def test_rtt(self):
-        self.execute(RTT)
-        rtt = self.dataset_mgr.get("rtt")
-        print(rtt)
-        self.assertGreater(rtt, 0*ns)
-        self.assertLess(rtt, 100*ns)
-
-    @unittest.skipUnless(artiq_low_latency,
-                         "timings are dependent on CPU load and network conditions")
     def test_loopback(self):
         self.execute(Loopback)
         rtt = self.dataset_mgr.get("rtt")
@@ -208,8 +175,6 @@ class CoredeviceTest(ExperimentCase):
         count = self.dataset_mgr.get("count")
         self.assertEqual(count, 10)
 
-    @unittest.skipUnless(artiq_low_latency,
-                         "timings are dependent on CPU load and network conditions")
     def test_pulse_rate(self):
         self.execute(PulseRate)
         rate = self.dataset_mgr.get("pulse_rate")
@@ -217,12 +182,6 @@ class CoredeviceTest(ExperimentCase):
         self.assertGreater(rate, 100*ns)
         self.assertLess(rate, 2500*ns)
 
-    def test_loopback_count(self):
-        npulses = 2
-        self.execute(LoopbackCount, npulses=npulses)
-        count = self.dataset_mgr.get("count")
-        self.assertEqual(count, npulses)
-
     def test_underflow(self):
         with self.assertRaises(RTIOUnderflow):
             self.execute(Underflow)
diff --git a/examples/master/device_db.pyon b/examples/master/device_db.pyon
index e2fe7eed1..59b32de2f 100644
--- a/examples/master/device_db.pyon
+++ b/examples/master/device_db.pyon
@@ -157,7 +157,6 @@
         "command": "lda_controller -p {port} --bind {bind} --simulation"
     },
 
-    "ttl_inout": "pmt0",
     "ttl_out": "ttl0",
     "ttl_out_serdes": "ttl0",